Open access peer-reviewed chapter

Multifunctional Gemini Surfactants: Structure, Synthesis, Properties and Applications

Written By

Bogumil E. Brycki, Iwona H. Kowalczyk, Adrianna Szulc, Olga Kaczerewska and Marta Pakiet

Submitted: 05 October 2016 Reviewed: 23 March 2017 Published: 05 July 2017

DOI: 10.5772/intechopen.68755

From the Edited Volume

Application and Characterization of Surfactants

Edited by Reza Najjar

Chapter metrics overview

5,155 Chapter Downloads

View Full Metrics


Gemini cationic surfactants are compounds which are composed of two hydrophilic head groups and two hydrophobic tails linked by a spacer at the head groups or closed to them. The spacer can be either hydrophobic or hydrophilic. It can be rigid or flexible. The neutral charge of the molecule is retained by the presence of organic or inorganic counterions. Critical micelle concentrations (CMCs), surface tension (γ) and minimal inhibitory concentration (MIC) are dozen times lower than corresponding parameters of monomeric surfactants. The unique properties of gemini surfactants with a wide range of hydrophilic-lipophilic balance (HLB) make them a very useful, innovative material in detergents, cosmetics, personal care products, additives for paints and coatings, biocides, material science, organic synthesis, pharmacy, textiles, enhanced oil recovery, nanotechnology, petroleum and many other branches of life. A large number of papers concerning gemini surfactants have been published so far. This review presents a synthetic look at current work devoted to structure, synthesis and applications of gemini surfactants.


  • gemini surfactant
  • surface activity
  • antimicrobial activity
  • corrosion inhibitors
  • smart materials

1. Introduction

Everything in the world involves chemistry and chemicals. Chemistry is essential for our life and our existence in the material world. Without chemistry there would literally be nothing. The diversity of life and material forms is based on versatility of chemical compounds and interactions between them. Therefore, the better we know chemistry, the better we know our world. From among of over 120 millions of currently known organic and inorganic compounds [1], some of them have a very special meaning to facilitate our life. One of the very important and it seems to be irreplaceable groups of chemicals are surfactants.

The surfactant molecules contain at least two moieties, hydrophobic and hydrophilic one. Hydrophobic moiety is usually a straight or branched hydrocarbon or fluorocarbon chain with 8–18 carbon atoms, whereas hydrophilic moiety is a polar or ionic group. The balance between hydrophobic and hydrophilic parts, hydrophilic-lipophilic balance (HLB), is responsible for special properties of these amphiphilic compounds in solutions such as adsorption on the surfaces and interfaces and formation of self-assembly aggregates. The driving force for amphiphiles’ adsorption is the lowering of the free energy of the phase boundary that provides to lowering the surface and interface tension.

This fundamental feature of amphiphiles is a base of their very wide practical applications. Surfactants are used in almost every field of our activities. They find application in detergents [2], in personal care products [3], as additives for paints and coatings [4], as dyestuffs [5, 6], as biocides [710], in material science [2], in organic synthesis [11, 12], in pharmacy [5, 13], in textiles and leather [2, 14, 15], in agrochemicals [16], in fibres [1719], in plastics [20], in food processing [21, 22], in petroleum industry for enhanced and tertiary oil recovery [2325], in environmental protection (oil slick dispersant) [26, 27] and in explosives [28]. Surfactants are also used to replace traditional solvents, giving lower risk and reduced environmental impacts [29]. Surfactants can also play a key role in the development of technologies such as nano- and smart materials [30].

Currently, the global surfactant market has been segmented into anionic, cationic, non-ionic and amphoteric [31]. Anionic surfactants, like alkylbenzene sulfonates, α-olefin sulfonates, sulphates and ether sulphates, carboxylates, isethionates, taurates and phosphate surfactants held around 50% share of the global surfactant market. These surfactants are largely used in industrial and institutional cleaners and detergents. Cationic surfactants, like quaternary alkylammonium salts, exhibit mainly softening, antistatic, soil-repellent, antibacterial and corrosion inhibitory effects, whereas non-ionic surfactants, that is, alcohol ethoxylates, are suitable for cleaning purposes, as they are not sensitive to water hardness. Amphoteric (zwitterionic) surfactants, mainly derivatives of trimethyl glycine, are pH sensitive and have excellent dermatological properties. Besides, of these four main groups, there are also special surfactants, that is, fluorocarbon and silicone surfactants, sugar-based surfactants derived from mono- and polysaccharides, biosurfactants and polymeric surfactants. A very special group of surfactants are naturally occurring in living organisms’ amphipathic molecules, phospholipids, like phosphatidylcholine (lecithin) (Figure 1), phosphatidylserine, phosphatidylethanolamine (cephalin), phosphatidylinositol and sphingomyelin, with the main applications in drug delivery systems [32].

Figure 1.

Structure of lecithin.

The global surfactant market has been exceeded 15 million tons [31] and is expected to reach a valuation of US$28.8 billion by 2023, increasing at a 4.20% compound annual growth rate (CAGR) upon its 2014 value of close to US$20.3 billion [33].

An increasing use of surfactants is mainly driven by higher demand for personal care products, detergents, cleaners and industrial—anticorrosion and biocidal—products. This, in turn, is expected to lead to the introduction of innovative, more effective, surfactant-based products in the near future. The higher efficacy of surfactants is directly related to lower CMC and surface tension as well as the efficient emulgation and solubilization effects. Such profile of innovative surfactants is accomplished to a high extent by gemini surfactants [3436]. These compounds contain two hydrophilic head groups and two hydrophobic tails linked by a spacer at the head groups or closed to them. The structure of linker and its affinity to solvents can vary in a wide range. The gemini alkylammonium salts show unique surface and interfacial properties in aqueous solution. Critical micelle concentrations (CMCs) of gemini surfactants are usually much lower, up to hundred times, than CMCs of corresponding monomeric surfactants. The effectiveness of dimeric surfactants in lowering the surface tension is also much better than their monomeric analogues. The values of C20, that is, surfactant concentration at which the surface tension (γ) is lowered by 20 mN/m, are dozen times smaller for gemini surfactants than monomeric surfactants. Moreover, gemini surfactants can form in solution many morphological structures, like spherical, ellipsoidal, rod shape and worm-like micelles as well as vesicles and helical or tubular forms. These unusual properties of gemini surfactants are ground of their applications as emulsifiers, dispersants, coating agents and corrosion inhibitors. Dimeric quaternary ammonium salts are also the excellent microbiocides. The antimicrobial activity (minimal inhibitory concentration - MIC) of quaternary ammonium salts strongly depends on their hydrophilic-lipophilic balance (HLB) and the length of the spacer. The longer the spacer, the better the antimicrobial activity. It is because gemini surfactants with longer spacers are more flexible and easily connect with the negative-charged surface of bacteria or fungi.

To better understand the fascinating physicochemical and biological properties of gemini surfactants and their wide potent applications, we present a review of synthesis, structure, properties and applications of these compounds.


2. Structure

Gemini surfactants contain two hydrophilic head groups and two hydrophobic tails linked by a spacer at the head groups or closed to them. When both hydrophobic parts are the same and hydrophilic groups are identical, then gemini surfactant forms symmetric structure (Figures 24) [37].

Figure 2.

Structure of gemini surfactant with spacer at head groups.

Figure 3.

Structure of gemini surfactant with spacer in hydrophobic part.

Figure 4.

Bolaform of gemini surfactant and lysine-based gemini surfactant.

In contrast to symmetric dimeric surfactants are heterogeminis with two different, or the same, polar head groups and two different, or the same, hydrophobic groups (Figures 5 and 6) [38].

Figure 5.

Structure of heterogemini surfactant.

Figure 6.

Example of dissymmetric surfactant.

The substituents in gemini surfactants are responsible to high extent for behaviour of these compounds in solution and their possible applications. Some examples of a large group of substituents, both hydrophobic and hydrophilic, are shown in Figure 7.

Figure 7.

Examples of substituents in gemini surfactants.

Quaternary nitrogen atom usually exists in acyclic forms; however, there are many geminis with nitrogen involved in saturated and unsaturated rings (Figure 8).

Figure 8.

Nitrogen involved in saturated and unsaturated rings.

Compounds with nitrogen involved in annulene unsaturated ring have a very special character because a ring plays to some extent a role of spacer (Figure 9) [39].

Figure 9.

Annulene gemini surfactants.

The spacer can be either rigid or flexible with tendency to hydrophobicity or hydrophilicity (Figure 10). It is a very important part of gemini surfactant which regulates the adsorption on the surfaces and interfaces and formation of self-assembly aggregates.

Figure 10.

Examples of spacer in gemini surfactants.

The neutral charge of the molecule is retained by the presence of counterions, which can be organic or inorganic ones (Figure 11).

Figure 11.

Organic and inorganic counterions in gemini surfactants.

To get the anticipated properties of gemini surfactants, the structure has to be optimized by modification of HLB. It can be done by introduction of balanced polar or hydrophobic groups both to substituents and spacers. Polarity can be increased by ester, ether, amide, sulphide and cyclodextrin group [3941]. To increase hydrophobicity some fluorine groups [42] or a dehydroabietylamine derivative [43] can be introduced to substituent. To increase biodegradability some amide or ester groups, which facilitate the biodegradation should be also introduced [44].


3. Synthesis

The study of bisquaternary ammonium surfactants—gemini surfactants—has been commenced by Bunton and collaborators in 1974 [45]. They described the synthetic approach and kinetic of these nucleophilic reactions. Some years later Devinsky et al. synthesized a great variety of bisquaternary ammonium surfactants and investigated their surface activity and micellization [46]. A unique self-assembly behaviour of gemini surfactants in comparison to their monomeric analogues has been perceived by Zana [47] and Esumi et al. [48]. The first anionic dimeric salts with two sulphate groups and two alkyl chains have been synthesized by Okahra in 1990 [49]. Currently there are three main routes to obtain symmetric gemini surfactants, that is, (1) reaction of long-chain tertiary amines with dihalogenated substrates such as organic dibromides or dichlorides, (2) reaction of N,N,N′,N′-tetramethylpolymethylene diamines with alkyl halides and (3) reaction of long-chain tertiary amines with a haloalkylene oxide substrate, commonly epichlorohydrin (Figure 12).

Figure 12.

The general routes to prepare symmetric gemini surfactants.

The yield of the synthesis of the symmetrical gemini surfactants mainly depends on reactivity of dihalogenoalkanes and polarity and protic character of solvent [5052]. The best results are achieved in aprotic and polar solvents. Some of these reactions can also be carried out without solvent in mild conditions with very high yields [53].

Cationic gemini surfactants with ester bond as a spacer can be synthesized by the method given by Liao [54] and Gao (Figure 13) [55].

Figure 13.

The synthesis method for preparing ester derivatives of gemini surfactants.

The gemini ester quats (ethylene-bis-alanine-n- alkylesterquats bromides) TMEAL-n (Br) and (1,3-propylene-bis-alanine-n-alkylesterquats bromides) TMPAL-n (Br) were synthesized in two steps. In the first step, intermediates—alkyl 2-bromopropionates with 6, 8, 10, 12 and 14 carbon atoms in their alkyl chain—were obtained by acylation of the appropriate alkanols with 2-bromo-propanoyl bromide. In the second step, the alkyl 2-bromopropionates were reacted with N,N,N′,N′-tetramethyl-ethylene diamine (for TMEAL-n synthesis) or N,N,N′,N′-tetramethyl-propylene diamine (for TMPAL-n synthesis). Bis-quaternization was performed in the acetonitrile solution (Figure 14) [56].

Figure 14.

Bis-quaternization ester derivatives of gemini surfactant.

Most of the amino acid-based gemini surfactants synthesized so far are N-alkylamides and ester derivatives of the amino acids (N-alkanoyl derivatives, N-alkylamides and O-alkyl esters). These compounds are prepared by condensation reactions at either the amino or the carboxyl group of the amino acid [57].

Cationic serine-based gemini surfactants were obtained by the reductive amination of glutaraldehyde with the O-protected amino acid. To avoid the cyclization reaction, the dialdehyde substrates must contain very short or very long alkyl substituent. Another possibility is to prepare N-alkyl derivatives before introduction of the linker [58].

Most studies on the synthesis and biological evaluation of the amino acid gemini surfactants address arginine derivatives [59]. A few reports on lysine-, glycine- and cystine-based gemini surfactants have also been published [6063].

Sugar-based gemini surfactant (polymethylene-α,ω-bis(N,N-dialkyl-N-deoxy-d-glucitolammonium iodides)) was synthesized in multistep reactions, by a condensation of d-glucose with diamine, followed by reduction of d-glucopyranosyle ring with sodium borohydride and a reductive alkylation with aliphatic aldehydes, containing from 6 to 12 carbon atoms, in the presence of sodium cyanoborohydride as a selective reducing agent. Quaternization of nitrogen atoms by aliphatic n-iodides was the last step of the reaction procedure [64].

Zwitterionic gemini surfactants contain positive and negative atoms inside one molecule [64]. The synthesis of zwitterionic geminis is quite complicated; therefore only a few reports appeared so far. The work of Peresypkin and Menger [65] concerns a preparation of zwitterionic gemini surfactant with phosphodiester as a negatively charged group and a positively charged quaternary ammonium salt separated by two pairs of methylene groups [Cx–PO4–(CH2)2–N+(CH3)2–Cy, where x + y = 22]. Yoshimura et al. [66, 67] synthesized sulfobetaine-type zwitterionic gemini surfactants and heterogemini zwitterionic surfactants containing ammonium and carboxylate head groups. Xie et al. [68] offered a simple method for synthesizing alkylbetaine zwitterionic gemini surfactants based on 1,2-bis[N-methyl-N-carboxymethyl-alkylammonium] ethane (CnAb, where n represents a hydrocarbon chain with a length of 8, 10, 12 or 14) that were synthesized by alkylation of N,N-dimethylethylenediamine with an alkyl bromide, followed by reaction with sodium 2-bromoacetate.

Quagliotto et al. [69] synthesized a series of pyridinium cationic gemini surfactants by quaternization of the 2,2′-(R,ω-alkanediyl)bispyridines with N-alkylating agents. Limei Zhou et al. [70] synthetized novel gemini pyridinium surfactants by using 1,4-dibromobutane and R-alkyl pyridine.

Gemini surfactants with a non-Hückel diaza[12]annulene core were synthesized by treating N-(2,4-dinitrophenyl) pyridinium chloride with long-chain amines (Figure 15) [71, 72].

Figure 15.

Synthesis of annulene derivatives.

Dissymmetric gemini surfactants contain two nonidentical polar head groups and two different (or identical) lengths of alkyl tails according to Alami and Holmberg [73]. The first heterogemini surfactants containing quaternary ammonium and carboxylate head groups and two dodecyl or tetradecyl tails have been obtained by Jaeger et al. [74]. Some other dissymmetric gemini cationic surfactants with hydroxyl group in the spacer and different long carboxylic acid dimethylethylamine esters as cationic parts [75].

Surface activity of heterogeminis strongly depends on degree of the asymmetry. For pyrene-based dissymmetric gemini surfactants synthesized in five-step reactions (Figure 16) [76], the Krafft temperatures increase with the increase of the alkyl chain length. Similarly, CMC values are much lower than those of their symmetrical counterparts.

Figure 16.

Preparation of dissymmetric gemini surfactant.

Gemini surfactants can be also prepared in microwave-assisted organic syntheses. The usefulness of 5.8-GHz microwaves is demonstrated by the solvent-free synthesis of 2-allylphenol through a Claisen rearrangement process and by the synthesis of the C12–C2–C12 [77].


4. Analytical methods

A large number of analytical methods can be applied to study gemini surfactants and their structure, surface behaviour and interaction with polymers and other materials.

To determine structures of gemini surfactants, the standard spectroscopic methods, nuclear magnetic resonance (NMR) spectroscopy (1H, 13C and 31P), mass spectrometry (fast atom bombardment) and Fourier-transformed infrared spectroscopy (FT-IR) are mostly used.

For cationic gemini surfactants, 1H NMR chemical shift values (δ/ppm) are generally higher for head group protons because of the proximity of the positive charge on the nitrogen atom. In turn, protons of hydrocarbon chain at highly hydrophobic section of the surfactant residue in the core portion of micelle are highly shielded; hence 1H NMR peaks are observed in lower ppm regions [78].

The variation of the chemical shifts due to the hydrophobicity can be used as a method to study of the aggregation process. For example, the correlation between 1H NMR shifts and ([gemini]/CMC)−1 for the terminal methyl group of the chains suggests the presence of transient proximity between the methyl group and the annulene ring system. Diffusion coefficients from pulsed gradient spin-echo (PGSE) NMR experiments reveal that the annulene gemini micelles are similar in size and shape to those of simple monomeric surfactants [71].

The very interesting results have also been observed for 1H NMR study of two series of quaternary ammonium gemini surfactants 12-s-12 and 14-s-14 at concentrations below their CMC in aqueous solutions. The analysis of self-diffusion coefficients, changes in chemical shift, line width and line shapes indicates the premicellization of these two series of geminis below their CMC values [79]. NMR technique has been also applied to study of the binding isotherms of the surfactants to the polymers [7982]. McLachlan and Marangoni have investigated the interactions between poly(styrenesulfonate) (PSS), dodecyltrimethylammonium bromide (DTAB) and cationic gemini surfactants (12-s-12) [80]. For the gemini cationic surfactants, the NMR chemical shifts indicate that the manner in which the gemini surfactants self-assemble with the polymer is dependent on the spacer length of the surfactant. The 1H chemical differences indicate that the manner in which the DTAB and the long-spacer gemini surfactants interact with the PSS is fundamentally similar, whereas the short-spacer gemini surfactants have a different 1H chemical shift difference pattern for the spacer and chain protons; this may indicate subtle differences in the nature of the binding of these cationic surfactants to the polyanions.

The unusual self-assembly behaviour of gemini surfactants possesses challenging puzzles to theoretical investigations [83]. In view of the above, the cationic gemini surfactant designated as 16-E2-16 (ethane-1,2-diyl bis(N,N-dimethyl-N-hexadecylammoniumacetoxy)-dichloride) was obtained and investigated as a corrosion inhibitor for mild steel (MS) in 1 M HCl solution by refined analytical methods and weight loss measurements. Moreover, the inhibition effect of the investigated compound was analysed by DFT method [84].

Cationic gemini surfactants of the m-2-m type have been investigated with luminescence probing and neutron scattering [85]. Dynamic light scattering (DLS) shows that the surfactant interacts with the polymer at low concentrations and 12-2-12 mixed systems grow to large aggregates with surfactant concentration. It is also confirmed that the longer the hydrocarbon chain length of surfactant, the stronger the interactions.

The molecular composition of each G12-s and G18:1-s gemini surfactant was determined by quadrupole time-of-flight mass spectrometry analysis (QqToF-MS). The fragmentation pattern of the investigated compounds was done by QqToF-MS=MS and showed that the geminis share fragmentation patterns that are specific to their respective gemini surfactant families. At present, a study of some gemini surfactant families are directed to identify for each gemini surfactant two or three product ions with unique m/z values which can be utilized in multiple-reaction monitoring and analysis of biological samples [86].

The combined MS and DFT methods can be very useful for studying competitive SN2 and E2 reactions in the gas phase. The M2+X- pairs formed from hexadecyldiyl-R,ω-bis(dimethylalkylammonium) surfactants are stable in the ion trap of spectrometer, which is consistent with DFT computations of the bolaform analogues. It shows that M2+X- pairs are extremely stable in the gas phase [87].

The self-aggregation behaviour of gemini surfactant 12-2-12 (ethanediyl-1,2-bis(dimethyldodecylammonium bromide)) in water was investigated by dielectric relaxation spectroscopy (DRS) over a frequency range from 40 Hz to 110 MHz [88]. A defined, widely distributed dielectric relaxation was observed in the 107–108 Hz frequency range for all micelle suspensions; the relaxation mechanism was recognized as the interfacial polarization between the micelles and solution medium.

Currently, the most common method for quantitative determination of surfactants is high-performance liquid chromatography (HPLC) [89, 90] and GC-MS method [91].

Many HPLC methods for the determination of quaternary alkylammonium compounds have been reported. Wee and Kennedy reported a normal phase method for the determination of cationic surfactants without separation of the homologous series in environment samples [92]. One of the methods which can differentiate and quantitate the homolog mixture is high-performance capillary electrophoresis (HPCE) that separates compounds in an electric field according to their charge and size [93, 94].

One of the simplest methods of determining the amount of surfactants in the sample is titration. The first method is turbidimetric titration. In this method cationic surfactants are titrated with anionic surfactants. The next method is a two-phase colorimetric titration. Two-phase titration was first described by Epton in 1947 [95]. Soon it became a commonly used method. This method was developed as a standard method and published as ASTM, BSI and DIN standards [9699].

Another method is potentiometric titration in the aqueous phase. The potential of a solution containing surfactants is measured as a function of added titrant. The potential of the sample is measured by means of electrode-sensitive surfactants [100].


5. Surface properties

One of the fundamental properties of surfactants is their tendency to adsorb at interfaces. It affects surface tension reduction because of their dual chemical nature [35, 101, 102]. The surface tension (γ) of pure water is 72 mN/m [103]. The ability to reduce it by surfactants depends on the replacement of molecules of solvent at the interface by molecules of surfactants. Mechanism of action of cationic gemini surfactants based on the adsorption of hydrophilic groups (positively charged nitrogen atoms) onto a polar phase and hydrophobic groups in a nonpolar phase. These phenomena are characterized by an efficiency factor pC20 which is a concentration of surfactants when the tension is reduced by 20 mN/m [101]. Gemini surfactants are better at lowering the surface tension than their monomeric analogues. The value of pC20 for DTAB is 2.3 (C20 = 5.25 mM) whilst for 12-2-12 is 3.78 (0.16 mM) [53, 104]. Higher pC20 means lowering surface tension by 20 mN/m at lower concentrations. Usually the value of surface tension is given at CMC (γCMC) which is a critical micelle concentration [105]. It is the concentration when monomeric molecules of surfactants abruptly assemble into aggregates called micelles [106] and they are in the balance. Critical micelle concentration can be estimated using different methods: conductivity measurements, surface tension measurements, UV-absorption spectroscopy, fluorescence spectroscopy, dynamic light scattering or dye solubilization [106]. Conductometry and tensiometry are the most popular and the easiest methods [35]. There are several factors affecting the value of CMC such as structure of surfactant (hydrophilic group, hydrophobic group and spacer) and temperature.

Gemini surfactants exhibit lower CMC values than conventional QAC which is connected with the number of hydrophilic groups. Monomeric quaternary ammonium salts have higher critical micelle concentrations than dimeric one [107, 108]. The relation between number of positively charged nitrogen atoms and the CMC is presented in Figure 17 [109].

Figure 17.

The correlation between number of hydrophilic groups and critical micelle concentration.

Lower CMC values for dimeric and oligomeric surfactants are connected with their packing into a micelle. Monomeric salts need more molecules to form micelles than dimeric. It is showed in Figure 18.

Figure 18.

Micelles made of monomeric and dimeric surfactants.

The structure of the hydrophobic groups has also a big impact on the CMC. Its value decreases as the carbon atom numbers increase [110]. The value is halved after addition of one methylene group to a straight hydrophobic chain [101]. The relationship between CMC and the length of the hydrocarbon tail, for compounds of m-s-m type, is shown in Figure 19 [111].

Figure 19.

The relationship between the number of carbon atoms in the hydrophobic chain and the CMC values.

Elongating the hydrocarbon chain makes the molecule more hydrophobic. The greater the hydrophobicity of the surfactant, the greater tendency to form micelles [112].

CMC can be also controlled by the type and the length of the spacer. At first, CMC gradually increases as the spacer becomes longer, up to four carbon atoms, and then for longer spacers, CMC again decreases [113]. The relationship between CMC and the length of the spacer for geminis of type 12-s-12 (s—number of carbon atoms in the spacer) surfactants is presented in Figure 20 [111]. This effect is due to the hydrophobicity of the spacer. The short spacers are fully extended on the air-water interface, whereas long spacers are much more hydrophobic and flexible; therefore they begin to fold into the air.

Figure 20.

Relationship between the number of carbon atom in the spacer(s) and the CMC value.

The introduction of a polar group like oxygen to the spacer causes an increase of CMC. For gemini surfactant 12-5-12, the CMC value is 1.03 mM [34] and increases to 1.35 mM with spacer containing oxygen atom [114]. The multiplication of oxygen units in the spacers exerts a similar effect, that is, an increase of the CMC value. For gemini surfactant 16-CH2CH2OCH2CH2-16, CMC is 0.004 mM, whilst for compound with triple oxygen units, that is, 16-CH2(CH2OCH2)3CH2-16, CMC value increases to 0.02 mM [115]. The presence of rigid spacers (unsaturated bond and benzene ring) also shifts the CMC to higher values. Some examples of CMC are presented in Table 1 [103, 114, 116118].

Table 1.

CMC values for gemini surfactants with a rigid spacer and their analogues with a flexible one.

The structure of the head groups, not only the number of them, affects aggregation behaviour [118, 119]. The exchange of methyl groups at charged nitrogen atom to ethyl ones in 12-4-12 decreases the CMC value from 0.99 to 0.59 mM [120]. The relationship between critical micelle concentration and the type of groups linked to quaternary nitrogen atom is presented in Figure 21.

Figure 21.

The relationship between CMC values and the kind of group in the hydrophilic part of the surfactant.

In contrast to the influence of hydrophilicity of the spacer on CMC, the increase of the hydrophilicity of the substituent significantly decreases CMC values. An example is shown in Figure 22.

Figure 22.

The CMC value for gemini surfactants modified by adding ethoxyl groups.

The exchange of one methyl group to hydroxyethyl group at nitrogen atom in 12-4-12 reduces CMC value 10 times, whereas the exchange of both methyl groups to hydroxyethyl substituents lowers CMC almost 1000 times in comparison to the starting compound [121, 122].

Temperature is also a factor which affects the aggregation behaviour. An increase of temperature in the beginning causes the decrease of CMC to minimum around 25°C, and then with further increase of temperature, CMC becomes higher [101]. These effects are directly related to hydration and dehydration of alkyl chain that are sensitive to temperature. The correlation between temperature and CMC values for 12-4-12 is presented in Figure 23 [105].

Figure 23.

Relationship between temperature and CMC of 12-4-12.

The shape of micelles may differ in a wide range, which mainly depends on the structure of surfactants. The most popular methods to estimate the shape of aggregates are dynamic light scattering, small-angle neutron scattering and NMR self-diffusion coefficients [101, 118, 123, 124]. It was noticed that gemini surfactants with short spacers usually form cylindrical micelles, the one with medium spacers form spherical micelles and those compounds with long spacers form mainly vesicles [111]. However, gemini surfactant 12-2-12 has been shown to form spherical shape micelles [113]. The assessment of the micelle shape is somewhat difficult because it depends not only on the structure of surfactant. The significant influences on geometry and structure of micelles are temperature, concentration, solution condition and ionic strength [115]. Geometrical construction of the surfactant aggregates can be determined by calculating critical packing parameter (P) [120]:


where Vhydrophobic is the volume of hydrophobic chain (for gemini surfactants Vhydrophobic = 2 V) and l0 is the length of hydrophobic chain (for gemini l0 = 2l). They are estimated by using Tanford’s expression:


where m is the carbon atom number of a single hydrophobic chain and a0 is the average packing area of the hydrophilic head group by a single surfactant molecule, usually for gemini surfactants a0 = 2 [120]. 0 < P > 1/3 indicates spherical micelles, 1/3 < P > ½—cylindrical, ½ < P > 1—vesicles or lamellar and P > 1—inverse micelles in nonpolar media [101, 120]. Unfortunately, very often calculated shape varies from those estimated based on experimental methods. Transmission electron microscopy (TEM) is very often used to attain a direct visualization of micelles. Using a precise bar, measuring the size of micelles is possible [120].

Other aggregation parameters can be calculated from surface tension measurements. One of the most important is the aggregation number (NA) which is the number of surfactant monomers obligatory for micelle formation [106]. The bigger the gemini surfactant (longer alkyl chains, longer spacer, etc.), the lower the NA [108, 123]. It is in a good agreement with the relationship between the structure of surfactant and its CMC value. πCMC is an effectiveness defined as a difference between surface tension of a pure water and the surface tension of a solution of the surfactant at the CMC. This value can be used to compare surfactants within one series. The lowest value of πCMC belongs to the lowest surface-active analogue [112, 125]. The amounts of surfactant molecules adsorbed at the surface Γmax are estimated from the slopes of straight lines in the plot of surface tension vs. logarithmic concentration drawn in the concentration region below the CMC according to Gibbs adsorption isotherm:


The number of ionic species (n) at the interface varies with the surfactant concentration in the solution [125]. The minimum surface area per molecule (Amin) can be calculated from the equation:


where N is an Avogadro number [124]. Amin increases with increasing the length of the spacer and the length of the hydrophobic chains [105, 111].

Free Gibbs energy of micellization (ΔGmic) gives information about the nature of the aggregation process. The energy for gemini surfactants is calculated from an equation proposed by Zana [126]:


B is the counterion binding parameter which gives the average number of counterions per surfactant ion in the micelle and can be estimated from the ratio of the slopes of conductometry measurements (conductivity vs. concentration) [127]. Negative values of ΔGmic indicate that the process of micellization is spontaneous. ΔGmic increases in the negative direction by increasing hydrophobic character [128]. Figure 24 presents the relationship between the length of the spacer and ΔGmic [113]. S = 0 represents a monomeric cationic surfactant, DTAB. It is noticed that ΔGmic for gemini surfactant is much lower than for DTAB which means that forming micelles by dimeric salts is more favourable.

Figure 24.

The relationship between the Gibbs free energy of micellization and the number of carbon atom is in the spacer(s).

Using values of ΔGmic at different temperatures, other thermodynamic parameters can be calculated: entropy (ΔSmic), enthalpy (ΔHmic) of micellization and free energy of adsorption (ΔGads) by following equations:


Positive value of entropy indicates that the process of micellization is favoured. ΔHmic < 0 indicates an exothermic process whereas ΔHmic > 0 an endothermic. A negative value of ΔGads means that process of adsorption is spontaneous and usually increases by increasing temperature and the length of hydrophobic chain [106, 112, 113, 120, 128]. Moreover, if the value is more negative than ΔGmic, the molecules of surfactants tend to adsorb at the air-water interface until complete surface coverage and afterwards micelles are formed [128].


6. Biological activity

6.1. Antimicrobial activity

Microorganisms are essential for a large number of metabolic and biotechnology processes. However, they are also responsible for diseases and demises as well as biodeterioration of technical materials like wood, paper, textiles, paints, stonework and steel. To reduce this considerable risk, the chemical compounds with biocidal activity—microbiocides—have been usually used. Microbiocides include some phenols and their derivatives, organic and inorganic halogen compounds, oxidizing substances, quaternary ammonium compounds, alcohols, aldehydes and organic and inorganic acids [9, 64, 129132]. The most important group of microbiocides is quaternary ammonium compounds (QAC) because of their wide spectrum of biocidal activity, the safety of applications and low costs. Quaternary ammonium salts belong to lytic membrane-active microbiocides [133135].

Mechanism of their biocidal activity begins with adsorption of quaternary ammonium cation on negatively charged cell surface. Subsequently long hydrocarbon chains can diffuse through the bilayer of the cell, which increases the hydrophobicity of the bacterial cell membrane and provokes disruption of the cytoplasmatic membrane. Damage of the membrane results in the release of potassium ions and other low molecular weight cytoplasmatic constituents, finally leading to the death of the microorganism cell [136138]. Biocidal activity of the microbiocide is usually performed with minimum inhibitory concentration (MIC), that is, minimal concentration of compound which inhibits the growth of microorganism. MIC are affected by several factors like concentration of microbiocide, time of the contact, pH, temperature, the presence of organic matter or other compounds. Moreover MIC strongly depends on the nature, numbers, location and condition of the microorganism [139].

MIC could be determined by the broth or agar dilution method [140, 141] and expressed in the concentration units. Antimicrobial activity can be also expressed as a zone of inhibition by diffusion method. This method has many limitations, which mainly depend on diffusion ability of microbiocide. According to Klančnik, there are no straight correlations between these two methods [142].

The biocidal activity of gemini surfactants depends on the type of microorganisms. Gram-positive bacteria are more sensitive than the Gram-negative bacteria to ammonium microbiocide. This is due to morphology of the cell membranes. Gram-positive bacteria cell membranes are composed of peptidoglycan layers, which could be easily penetrated by surfactant, whereas Gram-negative cell membranes are mainly composed of lipopolysaccharides and proteins that restrict the entrance of microbiocides [137]. In general, the sensitivity of the microorganisms to gemini alkylammonium microbiocide decreases in the order: Gram-positive bacteria > fungi > Gram-negative bacteria [143]. Biocidal activity also depends on the strain of the microorganism. The environmental strains are more resistant than laboratory strains [144].

Structure of the microbiocide is the most important factor affecting antimicrobial activity. Gemini alkylammonium salts are much better microbiocides than their monomeric analogues. MIC values of geminis are usually 17–70 folds lower than MIC of single analogue QAC. For example, MICs against Staphylococcus aureus are 0.0036 [μM] for gemini [12-6-12] and 0.252 [μM] for dodecyltrimethylammonium bromide (DTAB) [144]. This is due to the fact that gemini surfactants posses not only double positive-charged nitrogen atoms but also two long lipophilic substituents. The adsorption on the microorganism cell wall and subsequent penetration of the bilayer is more efficient [138]. It could be said that antimicrobial activity increased with numbers of quaternary ammonium cations in the molecule, but Paniak et al. showed that number of charged nitrogens was not key determinant of bioactivity of ammonium surfactants [145].

Conventional gemini alkylammonium salts could be modified by the change of number of carbon atoms in the substituent or in the spacer. Compounds, which have 10–14 carbon atoms in the substituent, are more active against bacteria than others (Figure 25) [146]. The shorter substituents are too short to effectively penetrate the membrane. In turn the long substituents have a tendency to coil upwards loosing the ability to penetrate a cell wall. This is consistent with the parabolic relationship of MIC vs. the length of the substituent for monomeric QAC [129, 138].

Figure 25.

The relationship between MIC against S. aureus and Escherichia coli and a number of carbon atoms in the substituents in ethylene-1,2-bis(N,N-dimethyl-N-alkylammonium bromides).

The antimicrobial activity depends not only on the length of the substituent but also is dependent on the length of spacer [76, 137, 143, 147, 148]. In general, the longer the spacer, the better the antimicrobial activity (Figure 26) [77]. The longer spacers allow to better adjust of geminis to cell surface.

Figure 26.

The relationship between MIC and a number of carbon atoms in spacer of polimethylene-α,ω,-bis(N,N-dimethyl-N-dodecylammonium bromides).

Tatsumi et al. compared antimicrobial activity of gemini surfactants with flexible and rigid spacers. In the case of surfactants with fourth carbon atom in the spacer, more effective are compounds with unsaturated bond in the linker [149]. Another possibility of stiffening of spacer is to introduce a ring. Martín et al. showed that the nature of the ring (aromatic or saturated) does not influence the antimicrobial activity of gemini surfactants [150].

The antimicrobial activity of gemini alkylammonium salts strongly depends on their hydrophilic-lipophilic balance (HLB), according to the equation log1/MIC = a+blogP+C[logP]2, where P is octanol-water coefficient, which characterizes HLB of the molecule [138, 151, 152].

Antimicrobial activity of geminis with hydrophilic spacers modified by ester groups [148, 153155], ether groups [156], amide groups [157, 158], amine group [145], phosphoryl group [159] and their antimicrobial has been frequently studied. It is important to note that there is no simple relationship between different types of hydrophilic groups in the spacer and antimicrobial activity of gemini surfactants. For the same type of the hydrophilic spacer, antimicrobial activity of geminis depends on the length of the alkyl substituent [145, 154].

Gemini surfactants with higher HLB could be also obtained by introduction ester groups [160162], amide group [163165] or hydroxyl group [166, 167] to alkyl chain. These compounds possess usually better antifungal activity than corresponding classical gemini surfactant.

In general, the increase of hydrophilicity causes the better antimicrobial efficacy of gemini surfactants [164, 168170].

Gemini alkylammoniums with two hydroxyethyl groups, [12-4-12] diethanol (DEA) show higher antimicrobial activity than monohydroxyethyl derivative [12-4-12] monoethanol (MEA). The latter one in turn is better than compounds without hydroxyl groups [12-4-12]. The same trend is observed for monomeric analogues with two hydroxyethyl groups DTAB-DEA, one DTAB-MEA and one DTAB (Figure 27) [170].

Figure 27.

Antimicrobial activity of hydroxylated surfactants against Bacillus subtilis (MEA monoethanol, DEA diethanol).

6.2. Biodegradability

The susceptibility of gemini surfactants to biodegradation is the objects of many tests. The alteration of chemical structure of a substance changing its properties is defined as primary biodegradation, whereas mineralization to carbon dioxide, mineral salts and biomass is an ultimate biodegradation [171]. Surfactants are called to be easily biodegradable if at least 60% biodegradation occurred during 28 days [171, 172].

Martin et al. studied biodegradation of gemini surfactants with phenyl or cyclohexyl ring in the spacer. Whereas monomeric analogues are biodegradable (especially one with phenyl ring), gemini surfactants show no biodegradability [150]. Due to excellent antimicrobial activity, gemini alkylammonium surfactants are considered as hard (or no) biodegradable. The high biological activity of cationic gemini surfactants might have a negative impact on their biodegradation. Modification of spacer to increase hydrophilicity of the surfactant molecule does not significantly change biodegradability of geminis [171]. Gemini surfactants with sugar substituents, like gemini alkyldeoxy-D-glucitolammonium salts, show a susceptibility to biodegradation in the range 20–32%. The degree of biodegradability depends on the length of the alkyl chain. The longer the hydrocarbon substituent or spacer, the lower the biodegradability [172]. Amino acid-based gemini surfactants are biodegradable to even 60%; however, their single analogues degrade rapidly [173]. Modification of the structure (spacer or substituent) with easily hydrolysed groups can significantly affect biodegradability. The widely described easily biodegradable gemini surfactants are that with ester bonds [125, 148, 174177] (Table 2) [176, 178].

Table 2.

Biodegradability of gemini surfactants with ester bond in the substituent or in the spacer.

Another possibility to enhance the biodegradability of cationic surfactants is the use of immobilized consortium of microorganisms in Ca-alginate beads. This way allows the biodegradation of QAC up to 100% [179]. This method was applied to monomeric cationic surfactants; however, it is very possible that this would work also for gemini surfactants.

The crucial points to biodegrade chemical compounds, not only cationic surfactants, are the concerted activity of two or more groups of bacteria to fulfil enzymatic capabilities [181]. Moreover, there are no simple relationships between biocidal activity of gemini surfactants and their biodegradability.

6.3. Hemolycity

Gemini alkylammonium surfactants possess amphiphilic character and can interact with various surface, also with the membrane of erythrocytes. Łuczyński et al. report that the hydrocarbon chains of the gemini surfactants penetrate the hydrophobic lipid bilayer of the erythrocyte membrane, which causes weakness of the interaction between the lipid molecules, leading to lysis of the cell [56]. The haemolytic activity of the surfactants is usually expressed as HC50, that is, concentration that induces the haemolysis of 50% of the total number of erythrocytes [164], and it depends strongly on structure of surfactants. Koziróg et al. notice that gemini [12-6-12] did not exhibit haemolytic activity at MIC against Candida albicans, whilst monomeric surfactant DTAB at the same MIC caused a slight haemolysis of erythrocyte [144]. Similar conclusions have been described for geminis with ester group in the spacer [153, 180] and for amino acid-based gemini surfactants [181]. Łuczyński et al. have shown that haemolytic activity depends on the alkyl chain length, whilst compounds with 10 and 12 carbon atoms exhibit the highest haemolytic activity (the lowest HC50) (Figure 28). Surfactants with shorter alkyl chain induce haemolysis only at very high concentration. Also single-chain analogue shows haemolytic activity comparable with gemini with the same length of the alkyl chain [56]. Zhou has shown that HC50 of geminis is the highest for decyl, dodecyl and tetradecyl substituents that correspond to their high antimicrobial activity [182].

Figure 28.

Comparison of HC50 of gemini surfactant (TMEAL-n) and its monomer analogue (DMALM).

Hoque et al. studied haemolytic activity of amide-based gemini surfactants with different lengths of spacer. He found that the increase of the spacer length causes the increase of haemolicity (Figure 29) [164]. It is a result of an increasing hydrophobicity of gemini surfactants investigated. The similar results have been described for amino acid-based gemini surfactants; haemolytic power is higher for the compounds with more hydrophobic content, that is, with longer spacer and alkyl chain lengths [173, 181].

Figure 29.

Comparison of HC50 of gemini surfactant (AMID-Gs) and its monomer analogue Amid-QAC.

6.4. Cytotoxicity

Gemini alkylammonium surfactants are tested as nonviral gene vectors, so their cytotoxicity has to be studied. It is usually specified by the IC50 value i.e. the concentration of the compound (in μM) that attenuates the living cell survival to 50% [183]. IC50 depends on the structure of surfactants. For gemini surfactant with fixed length of spacer, cytotoxicity decreases as the length of alkyl chain increases (Figure 30). Moreover, for gemini surfactant with fixed length of alkyl substituent, IC50 decreases as number of methylene groups in spacer increases from 2 to 8 and then increases as number of methylene groups in spacer increases up to 12. These changes are very similar to those observed for MIC values. IC50 values show that monomeric surfactants are more cytotoxic than gemini ones, for example, IC50 of CTAB are 10.3 and 8.0 μM towards C6 and HEK293 cells, whilst IC50 of 16-4-16 are 3.5 and 4.1 μM, respectively [137]. Cytotoxicity also depends on the structure of head groups. Chauhan et al. find that pyridinium-gemini surfactant possesses lower cytotoxicity towards BV2 and C6 glioma cells than conventional gemini surfactants [14-2-14] [183].

Figure 30.

Cytotoxicity of gemini surfactants against BV2 and C6 glioma cells [185].

Due to the structure of gemini alkylammonium surfactants and their ability to penetrate biological membranes, they can be potentially used as skin permeation enhancers. Almeida et al. studied cytotoxicity towards NCTC 2544 cell line, a human skin keratinocyte cell line of several dicationic gemini surfactants, and compared with a commercial single-tail surfactant (DTAB) [184]. For the lower concentrations tested (up to 10 mM), none of gemini surfactant reveals a significant cytotoxicity upon the cellular line. However, over 25-mM toxicity is observed for some of them. Because gemini surfactants are more effective in disrupting the membrane than the single-tail counterpart, it means that a low amount of gemini, below threshold toxicity, may be needed to achieve the same effect of a significantly higher amount of DTAB. Silva et al. have shown that gemini surfactants are promising candidates, directed at permeation enhancing of hydrophilic drugs. They possess similar cytotoxic profiles and are even a little more effective than Azone (the most effective permeation enhancer for ketoprofen) [185].

6.5. Aquatic toxicity

The increasing use of gemini alkylammonium surfactants entails the need to define their biological profile, especially toxicity to aquatic organisms. For this purpose selected model organisms highly sensitive to pollution are used. Usually determined parameter is IC50 i.e. concentration of surfactants to immobilize 50% of organisms. Garcia et al. studied aquatic toxicity to Daphnia magna of several gemini surfactants with dodecyl substituent and different spacers (Figure 31) (dodecyltrimethylammonium bromide, DTAB; 1,6-hexamethylene-bis(N-dodecyl-N,N-dimethylammonium) dibromide, 12-6-12; 3-oxa-1,5-pentamethylene-bis(N-dodecyl-N,N-dimethylammonium) dichloride, 12-O-12; 3-azamethyl-1,5-bis(N-dodecyl-N,N-dimethylammonium) dibromide, 3N-12; 1,4-bis-[N-(1-dodecyl)-N,N-dimethylammoniummethyl]benzene dibromide, QSB2-12; and 1,6-hexamethylene-bis(N-dodecyl-N-hydroxyethyl-N-methylammonium) dibromide, G6-MOH-12). They find that aquatic toxicity decreases with increasing the hydrophilicity of the surfactant molecule. The structure of the spacer, rigid (benzene ring) or flexible (alkyl chain), has no significant effect on the acute toxicity to D. magna. Comparing the acute toxicity of gemini surfactants with that of monomeric surfactants DTAB (IC50 = 0.35 mg/l), dimeric surfactants are less toxic than monomeric surfactants [171]. Similar results were observed for amino acid-based gemini surfactants [173]. These compounds are less toxic to freshwater D. magna and seawater Photobacterium phosphoreum than conventional monomeric ammonium salts [181].

Figure 31.

Aquatic toxicity to D. magna of DTAB and gemini surfactant with hydrophilicity of the surfactant molecule.


7. Anticorrosion activity

Corrosion is a process of deterioration (degradation) of materials’ properties due to the interactions between a surface and an environment [186], which leads to changes in the material properties because of a disintegration of the structure of the material. The process destroys surfaces of the metals (iron, aluminium and copper) but also non-metallic materials (concrete, wood, glass and paper) [187, 188]. Usually a term “corrosion” is booked for the deterioration of metals, and according to a definition given by the American Section of the International Association for Testing Materials (ASTM), it is the chemical or electrochemical reaction between a material, usually a metal, and its environment that produces a deterioration of the material and its properties [189]. The problem of corrosion affects many areas of industries, oil and gas [190], electronic [191], food, paint, coating [192], marine, chemical [193], automotive and in daily life [176], by destroying metallic equipment, pipelines, vessels, storage tanks [190], heaters and electrical power lines [191] and leading to scale results in reduced heat transfer, loss of production capacity and energy loss [194]. Corrosion is induced by acids that are extensively used in industry [195]. Organic acids are used for preparation of chemicals, drugs, fibbers and other processes [196], whereas mineral acids (HCL, H2S, H2SO4 or H3PO4) are used for cleaning, acidification and pickling [190, 197]. Corrosion is a costly and dangerous process, which plays an important role in the field of economic and safety [194, 195]. The damages caused by corrosion can be estimated using different methods. The most popular are gravimetric (weight loss measurements) and electrochemical (potentiometry and electrochemical impedance spectroscopy) [198]. The rarer methods include spectroscopic (UV-VIS) [84], volumetric (amount of released hydrogen), analytical (assay of metal ions) or radiography (using radiation) [186, 188, 199, 200]. The morphology of destroyed metal surface is analysed using microscopes: scanning electron microscope (SEM) or atomic force microscope (AFM) [199].

In order to reduce the corrosion of metallic materials, several methods have been applied: electrochemical protection (anodic and cathodic), coatings (metallic and non-metallic) and corrosion inhibitors [187, 201205]. Among them, the use of organic corrosion inhibitors, especially cationic gemini surfactants, is the most efficient and practical method [192], particularly to control acid-induced corrosion [84]. Corrosion inhibitors are chemical substances which, when added, in a small amount, to the corrosive environment, significantly decreases the corrosion rate of metals [194]. The general mechanism of action of organic corrosion inhibitors is based on adsorption of molecules of inhibitor onto a metal surface by displacing water molecules and forming a protective film [191, 206]. The adsorption process can be physical (electrostatic interaction), chemical (donor-acceptor interaction) or mixed [200]. The process is influenced by the molecular structure of inhibitor (functional groups, aromaticity and electron density at donor atoms), surface charge of metal and type of electrolyte. Compounds with heteroatoms (N, O, S, P) [84] and π groups (multiple bonds, benzene ring) [207] have been found to be more efficient due to donation of a lone pair of electrons to a free orbital of the metal making them stronger adsorbed [190]. The order of corrosion inhibition is the reverse order of the electronegativity of the heteroatoms [208]:


It was noticed that in acid environment, heteroatoms are protonated which favours the physical adsorption and has increased the interest of quaternary ammonium salts (QAS) as corrosion inhibitors [128]. Cationic gemini surfactants are more efficient than monomeric QAS. It is related with lower values of CMC which is a key from the point of view of corrosion. Cationic surfactants reach the highest inhibition efficiency around CMC [200]. The corrosion rate (CR) of steel in 0.5 M HCl with addition of monomeric quaternary ammonium salts tetradecyl trimethyl ammonium bromide (TTAB) is higher than for dimeric analogue (1,4-butan-bis(tetradecyl dimethyl ammonium bromide) (14-4-14) [192] (Figure 32).

Figure 32.

Corrosion rate of steel in acid in the presence of monomeric and dimeric quaternary ammonium slats.

Two positively charged nitrogen atoms are better adsorbed onto the metal surface due to electrostatic interactions between cations and the negatively charged surface of metal which provides better protection [186, 209, 210]. The size and molecular weight of organic inhibitors have an impact on the effectiveness of action as corrosion inhibitors [209]. Increasing the length of the aliphatic chains increases the inhibition efficiency [192, 200, 211, 212]. The relationship of m-6-m surfactants (C = 1 mM) is presented in Figure 33 [200].

Figure 33.

The relationship between the length of the alkyl chains (m) and inhibition efficiency of aluminium in hydrochloric acid.

Another important factor is the length of the spacer. Surfactants with longer hydrocarbon spacer are more effective corrosion inhibitors [176, 199, 213215]. As an example, inhibition efficiency for gemini surfactants (C12H25)3N+(CH2)nN+(C12H25)3 (C = 5 mM) is presented in Figure 34 [215].

Figure 34.

Inhibition efficiency of inhibition corrosion of carbon steel in 1 M HCl.

Inhibition efficiency is related to corrosion-resistance properties of the metals. The adsorption of gemini surfactant molecules changes it by increasing the values of resistance of the metal which makes the material more resistant to corrosion [198]. Figure 35 presents the values of resistance of (C12H25)3N+(CH2)nN+(C12H25)3 and a value of blank sample, after immersion in acid without addition of inhibitors [215].

Figure 35.

The values of resistance for (C12H25)3N+(CH2)nN+(C12H25)3.

Introducing heteroatoms into a molecule promotes the inhibition behaviour. Due to lone electron pars, which can additionally interact with free metal orbitals, the adsorption is stronger and inhibition efficiency higher. Exchanging ethyl groups to ethoxyl groups in gemini surfactants with rigid spacer (Figure 36) increases the efficiency from 91.64 to 95.63% (C = 10 mM, carbon steel, 1 M HCl) [210].

Figure 36.

The structures of gemini surfactants with rigid spacer.

The standard energy of adsorption (ΔG0ads) gives information about the type of adsorption. Values up to −20 kJ/mol are related to the electrostatic interaction (physical adsorption), whereas more negative than −40 kJ/mol indicate chemisorption takes place. Negative values of ΔG0ads mean that the process of adsorption is spontaneous [209]. The energy of adsorption first decreases with increasing the length of the spacer and after reaching maximum starts decreasing which is related to the free energy of micellization (the same relation) [113]. Increasing the length of the alkyl chain increases the values of the ΔG0ads [199, 200]. The standard enthalpy of adsorption (ΔH0ads) provides valuable information about the mechanism of the corrosion inhibition. Chemisorption is attributed to an endothermic process (ΔH0ads > 0), whilst exothermic adsorption is represented by values lower than 0 [186] and is related to physical or mixed adsorption [215]. Another thermodynamic parameter which gives information of the adsorption process is entropy (ΔS0ads). Positive values are attributed to the increase of disorder due to the dissolution of metal and the adsorption of only one molecule of inhibitor by desorption of more water molecules [195].

Gemini surfactants which are used as commercial agents are not used alone. Special formulations are prepared based on synergistic effect. Thanks to that, the level of protection is higher, and very often due to synergism effect, less amount of surfactant is needed to protect the metal surface [193, 216219]. The biggest consumption of corrosion inhibitors based on cationic gemini surfactants belongs to petrochemical industry. Using the special formulations leads to decreasing corrosion rate and protection against deterioration during long time. Some formulations are already used in industries. Some of gemini surfactants are already patented as multifunctional corrosion inhibitors of ferrous metals that transported or stored crude oil and liquid fuels by the presence of acidic pollutants, sulphur compounds and water and equipment and pipes used in cooling systems that use water with a high concentration of divalent ions such as calcium and magnesium, which are the main cause of producing pitting corrosion in this environment [220] and also for inhibiting corrosion and biofouling of metallic surfaces in contact with corrosive fluids in gas- and oil-field applications [221]. All of them contain heteroatoms and π groups and exhibit good inhibition efficiency (more than 90%).


8. Special applications

The unique physicochemical and biological properties of gemini surfactants designate them to many applications in industry and pharmaceutical and biomedical branch where the safety profile of products must be optimized.

8.1. Nanoscience and nanotechnology

8.1.1. Gene therapy and bioimaging

Gemini alkylammonium surfactants are applied to introducing genes into cells, due to their ability to interact with DNA [222224]. This interaction must be strong enough to overcome the biologic membrane barrier and weak enough to release DNA in the right place in the cell. The gemini surfactant is shown to bind and compact DNA efficiently and form a “lipoplex”. The lipoplex can penetrate the outer membranes of many cell types, to appear in the cytoplasm encapsulated within endosomes. Escape from the endosome may be controlled by changes in the aggregation behaviour of the lipoplex as the pH decreases. DNA may be released from the lipoplex before entry into the nucleus, where the new gene can be expressed with high efficiency. Some gemini surfactants with sugar substituent, peptide moiety [225, 226] or cholesterol-based diquaternary ammonium gemini surfactant [227] were tested as a gene transfection vectors. It was recently shown that hydroxyethylated gemini surfactants [228], fluorinated bispyridinium gemini surfactants [229] and geminis derived from cysteine [230, 231] can be also used for this application.

Bioimaging is a very useful technique in the cancer diagnosis where the stable fluorescent marker is necessary. It has been recently shown that geminis like 12-2-12 and 12-6-12 are good stabilizers for model genetic material constructed from DNA and polysaccharide-based chitosan on nanoemulsion core containing IR-780 indocyanine as fluorescent marker [232].

8.1.2. Drug nanocarriers

Gemini surfactants can very easily change their morphological structures upon pH, temperature and salts [233239].

The reversible transition from micelles to other structures, especially to vesicles by changing pH, is very useful for drug delivery. Li et al. showed that gemini amino acid surfactants, where pH is the key driving force to control the aggregation behaviours, can be applied to build colloidal systems for delivering hydrophobic drugs or nutrition [240].

Similarly, Ref. [241] showed that geminis with morpholinium moieties exhibit high solubilization capacity towards a thymolphthalein as well as indomethacin, an inflammatory drug, exceeding that of reference amphiphiles.

8.1.3. Nanoparticles

Nanoparticles (NPs) have a lot of applications in medicine, physics, optics and electronics. The size and morphology of nanoparticles determine to high extent their properties and applications. These parameters can be mainly regulated by surfactants which act as soft templates or nanocontainers. The preparation of gold, silver and gold-silver alloy nanoparticles by seed-mediated method using gemini surfactant has been described by Tiwari et al. [242]. The obtained NPs were stable and were characterized by UV-vis, XPS, TEM, energy dispersive spectroscopy (EDS) and zeta potential techniques. The orientation of gemini surfactant molecules on the metal NPs has been determined by twisted intramolecular charge transfer (TICT).

A very interesting synthetic approach was developed by Wang et al. [243] for creating versatile hollow Au nanostructures. The reduction of Au(III) by ascorbic acid with the use of hexamethylene-1,6-bis(N-dodecyl-N,N-dimethylammonium bromide) (C12C6C12Br2) as a template agent leads to vesicle, capsule-like and tube-like aggregates which act as soft templates for hollow Au nanostructures upon further reduction of Au(I) to Au(0) by NaBH4. Gemini surfactant plays a crucial role in formation of the final structure. The electrostatic repulsion between head groups of gemini surfactant is greatly weakened as Au(III) is converted to Au(I), which is in favour of the construction of vesicle, capsule-like and tube-like aggregates. This method allows to prepare nanostructures of gold potentially useful for many applications.

The industrial scale production of monodispersed gold nanorods (AuNRs) has been described by Xu et al. [244]. By using gemini surfactants, the cost of the synthesis of high-quality AuNRs can be reduced by 90%. Moreover, varying the concentration of the surfactant, the shape of AuNRs can be tailored from straight nanorods to “dog bones”.

A special group of nanoparticles, quantum dots (QDs) [245], like lead telluride [246] hydrophobic quantum dots CdSe/ZnS [247] with strictly defined size and morphology are usually prepared with auxiliary of gemini surfactants.

8.1.4. Supramolecular solvents

Supramolecular solvents (SUPRAS) are nanostructured liquids made up of surfactant aggregates synthesized through a self-assembly process. This kind of solvent is mainly assigned to microextraction methods. Feizi et al. [248] applied a new gemini-based SUPRAS for the determination of methylparaben (MP), ethylparaben (EP) and propylparaben (PP) in cosmetics, beverages and water samples on the basis of pecation and Van der Waals interactions into the SUPRAS. The gemini-based SUPRAS followed by HPLC-UV has been found to have excellent detection sensitivity with a limit of detection (LOD, S/N = 3) of 0.5 mg/L for EP and PP and 0.7 mg/L for MP.

8.1.5. Interactions with proteins

Interactions between proteins and gemini surfactants derived from amino acids have also been investigated. This type of studies can help to understand the action of surfactants as denaturants and solubilizing agents for proteins that is important in medical and cosmetic branch. Gemini surfactants from glutamic acid exhibit different interactions with haemoglobin than their corresponding single-chain homolog. The gemini surfactants showed lower denaturing ability to haemoglobin, probably due to their bigger size, and the denaturation degree decreased when the spacer length increased. It was also observed that when the gemini surfactants content are low, the secondary structure of haemoglobin can be stabilized [249]. Takeda et al. reported the protective effect of gemini surfactants on thermal denaturation of BSA. The gemini surfactant studied by these authors consists of two glutamic acids as polar heads and a lysine as spacer. For this gemini surfactant, the protection of the recovery of the helicity of BSA appeared at lower concentration comparing to SDS due to the higher hydrophobicity of these compounds [250].

8.2. Technology

8.2.1. Solubilization

Gemini surfactants are very good solubilization agents [251]. Polycyclic aromatic hydrocarbons (PAHs) like anthracene, naphthalene, fluorene or pyrene [252, 253], which are organic pollutants, can be easily removed from water solution by the use of gemini surfactants. It significantly reduces the risk to the environment caused by these compounds [254]. Gemini surfactants are better for solubilization of PAH than their monomeric analogues. After mixing them together, values of molar solubilization ratio (MSR) are higher (Table 3) [252].

16-6-16 0.001 0.2110
CTAB 0.776 0.1236
16-6-16 + CTAB 0.0015 0.371

Table 3.

Molar solubilization of naphthalene of gemini surfactant, cationic surfactant and gemini-conventional mixtures.

Gemini surfactants are also efficient as solubilization agents of organic dyes (Quinizan, Sudan I, orange OT) which are used to colour textiles, waxes or oils [6, 255, 256]. Cationic surfactants promote the adsorption of solubilized dye to the surface, especially textile fiber surface which carries a negative charge [255].

Solubilization power of gemini surfactants increases with the elongation of the alkyl chain length [255, 257, 258] and elongation of the spacer length [257, 259] which is related to a larger size of micelles.

8.2.2. Dispersion

Another potential application of gemini surfactants due to their ability to form micelles is the capacity to disperse insoluble in water particles and form stable colloids. Carbon nanotubes (CNT) have unique electrical, optical and mechanical properties, and due to that, they are used as medical sensors, electronics and compatible materials [260]. However, because of strong Van der Waals interactions, the bundles are insoluble in water and common organic solvents which limit their potential applications [261, 262]. Cationic surfactants are widely used to disperse CNT in water even at low concentration giving stable solutions for long time [263]. Gold nanoparticles, because of their properties [264, 265], also have various potential applications in different areas, but to make them useful, forming stable nanofluids is required. It can be reached by using gemini surfactants as a stabilizer to prepare stable gold/oil nanofluids [264]. It has also been shown that gemini surfactants can effectively disperse hydrogels to form supramolecular, three-dimensional micellar-hybridized network [266268]. The formation of a spatial network of well-dispersed molecules is very significant for biomedical and optoelectronic applications.

8.2.3. Enhanced oil recovery

Traditional oil extraction methods produce depleted reservoirs that contain about 20–40% of trapped oil [269]. The remaining oil is trapped in porous media, due to the viscous, surface and interfacial forces, which results in poor displacement efficiency [270]. The implementation of advanced methods or their combinations to enable the recovery of residual oil is called enhanced oil recovery (EOR). Some techniques can be distinguished: thermal steam flooding (for heavy and extra heavy crude oil) [271], miscible gas flooding (for light, concentrated and volatile oil reservoirs) and chemical flooding (for medium or light reservoirs) [269]. Chemical flooding is one of the successful methods, especially the use of surfactants [272]. They are added into the flooding solution and improve the properties of reservoir fluids, to make them more conductive to extraction [273]. Tuning the capillary forces of the trapped oil and to achieve a complete miscibility, interfacial tension has to be reduced to the lowest possible value [274]. Due to their excellent surface-active properties, cationic gemini surfactants are great at lowering surface tension and changing the wettability [273]. Solutions of cationic surfactants, both monomeric (CTAB) and dimeric (16-2-16), were tested as mimic flooding solution (oil, n-dodecane; porous material, silica gel powder). It was noticed that the best results were achieved around CMC values, for CTAB 1 mM and for [16-2-16] 0.018 mM [273].

The highest oil recovery of 16-2-16 (68%) was reached at 0.018 mM whereas for CTAB (63%) at 0.6 mM (Figure 37) [273]. The tested gemini surfactant allows to achieve similar percent of oil recovery at lower concentration which makes the process more efficient [272, 275].

Figure 37.

Mimic oil recovery of CTAB and 16-2-16 aqueous solutions.


  1. 1. CAS Databases. CAS Databases [Internet]. Available from:
  2. 2. Myers D. Surfactant Science and Technology. 3rd ed. Hoboken, N.J: J. Wiley; 2006. 380 p
  3. 3. Rhein LD, editor. Surfactants in Personal Care Products and Decorative Cosmetics. 3rd ed. Boca Raton: CRC Press; 2007. 480 p. (Surfactant science series)
  4. 4. Karsa DR. Surfactants in Polymers, Coatings, Inks, and Adhesives. 1st ed. Blackwell; Bosa Roca, USA, 2003. (Sheffield Annual Surfactants Review)
  5. 5. Schramm LL, Stasiuk EN, Marangoni DG. Surfactants and their applications. Annual Reports on the Progress of Chemistry, Section C: Physical Chemistry. 2003;99:3-48
  6. 6. Tehrani-Bagha A, Holmberg K. Solubilization of hydrophobic dyes in surfactant solutions. Materials. 2013 Feb 21;6(2):580–608
  7. 7. Siedenbiedel F, Tiller JC. Antimicrobial polymers in solution and on surfaces: overview and functional principles. Polymers. 2012 Jan 9;4(4):46-71
  8. 8. Rahman PKSM, editor. Microbiotechnology Based Surfactants and Their Applications [Internet]. Frontiers Media SA; 2016 [cited 2017 Jan 20]. (Frontiers Research Topics). Available from:
  9. 9. Russell H& A, editor. Principles and Practice of Disinfection, Preservation, and Sterilization. 5th ed. Chichester, West Sussex: John Wiley & Sons; 2012
  10. 10. Zhou C, Wang F, Chen H, Li M, Qiao F, Liu Z, et al. Selective antimicrobial activities and action mechanism of micelles self-assembled by cationic oligomeric surfactants. ACS Applied Materials & Interfaces. 2016 Feb 17;8(6):4242-4249
  11. 11. John VT, Simmons B, McPherson GL, Bose A. Recent developments in materials synthesis in surfactant systems. Current Opinion in Colloid & Interface Science. 2002;7(5):288-295
  12. 12. Shinde PV, Kategaonkar AH, Shingate BB, Shingare MS. Surfactant catalyzed convenient and greener synthesis of tetrahydrobenzo[a]xanthene-11-ones at ambient temperature. Beilstein Journal of Organic Chemistry 2011 Jan 13;7:53-58
  13. 13. Akbar JR. Pharmaceutical Applications of Gemini Surfactants. 2011 [cited 2017 Jan 20]; Available from:
  14. 14. Sivaramakrishnan CN. The use of surfactants in the finishing of technical textiles. In: Advances in the Dyeing and Finishing of Technical Textiles [Internet]. Elsevier; 2013 [cited 2017 Jan 20]. pp. 199-235. Available from:
  15. 15. Le Marechal AM, Križanec B, Vajnhandl S, Valh JV. Textile finishing industry as an important source of organic pollutants. In: Organic Pollutants Ten Years After the Stockholm Convention-Environmental and Analytical Update [Internet]. Rijeka, Croatia: InTech; 2012 [cited 2017 Jan 20]. Available from:
  16. 16. Castro MJL, Ojeda C, Cirelli AF. Advances in surfactants for agrochemicals. Environmental Chemistry Letters. 2014 Mar;12(1):85-95
  17. 17. Shen AQ, Gleason B, McKinley GH, Stone HA. Fiber coating with surfactant solutions. Physics of Fluids. 2002 Nov;14(11):4055-4068
  18. 18. Ma J, Tang J, Cheng Q, Zhang H, Shinya N, Qin LC. Effects of surfactants on spinning carbon nanotube fibers by an electrophoretic method. Science and Technology of Advanced Materials. 2010 Dec;11(6):065005
  19. 19. Lin Y, Qiao Y, Cheng X, Yan Y, Li Z, Huang J. Hydrotropic salt promotes anionic surfactant self-assembly into vesicles and ultralong fibers. Journal of Colloid and Interface Science. 2012 Mar;369(1):238-244
  20. 20. Pritchard G, editor. Plastics Additives [Internet]. Dordrecht: Springer Netherlands; 1998 [cited 2017 Jan 20]. (Brewis D, Briggs D, editors. Polymer Science and Technology Series; Vol. 1). Available from:
  21. 21. Kralova I, Sjöblom J. Surfactants used in food industry: a review. Journal of Dispersion Science and Technology. 2009 Sep 30;30(9):1363-1383
  22. 22. Nitschke M, Silva SS. Recent food applications of microbial surfactants. Critical Reviews in Food Science and Nutrition. 2016 Jul 20
  23. 23. Raffa P, Broekhuis AA, Picchioni F. Polymeric surfactants for enhanced oil recovery: A review. Journal of Petroleum Science & Engineering. 2016 Sep;145:723-733
  24. 24. Maithufi MN, Joubert DJ, Klumperman B. Application of Gemini surfactants as diesel fuel wax dispersants. Energy & Fuels. 2011 Jan 20;25(1):162-171
  25. 25. Kumar N, Tyagi R. Industrial applications of dimeric surfactants: A review. Journal of Dispersion Science and Technology. 2014 Feb;35(2):205-214
  26. 26. Athas JC, Jun K, McCafferty C, Owoseni O, John VT, Raghavan SR. An effective dispersant for oil spills based on food-grade amphiphiles. Langmuir. 2014 Aug 12;30(31):9285-9294
  27. 27. Song D. Development of high efficient and low toxic oil spill dispersants based on sorbitol derivants nonionic surfactants and glycolipid biosurfactants. Journal of Environmental Protection. 2013;04(01):16-22
  28. 28. Lopes LRB, Soares VLP, Barcellos MTC, Mansur CRE. Desenvolvimento de surfatantes para aplicação na indústria de explosivos. Polímeros. 2014 Aug;24(4):474-477
  29. 29. Tornero V, Hanke G. Chemical contaminants entering the marine environment from sea-based sources: A review with a focus on European seas. Marine Pollution Bulletin. 2016 Nov;112(1–2):17-38
  30. 30. Brown P, Butts CP, Eastoe J. Stimuli-responsive surfactants. Soft Matter. 2013;9(8):2365
  31. 31. Transparency Market Research. Surfactants Market. Global Industry Analysis, Size, Share, Growth, Trends and Forecast, 2015–2023 [Internet]. Available from:
  32. 32. Li J, Wang X, Zhang T, Wang C, Huang Z, Luo X, et al. A review on phospholipids and their main applications in drug delivery systems. Asian Journal of Pharmaceutical Sciences. 2015 Apr;10(2):81-98
  33. 33. Transparency Market Research. Surfactants Market Rising at 4.20% CAGR from 2015–2023 due to Rising Demand for Detergents and Personal Care Products [Internet]. [cited 2017 Jan 16]. Available from:–2023-due-to-Rising-Demand-for-Detergents-and-Personal-Care-Products-Transparency-Market-Research.html
  34. 34. Zana R, Xia J. Gemini Surfactants: Synthesis, Interfacial and Solution-Phase Behavior, and Applications [Internet]. New York: Marcel Dekker; 2004 [cited 2017 Jan 20]. Available from:
  35. 35. Patial P, Chandel M. Synthesis, Characterization & Evaluation of Cationic Gemini Surfactants—Synthesis of Surfactants. Verlag, Germany: Lambert Academic Publishing; 2016
  36. 36. Ping M, Lu L, Cheng ZY. Synthesis and Properties of Gemini Surfactant (Chinese Edition). Chemical Industry Press; Beijing, China, 2014
  37. 37. Damen M, Cristóbal-Lecina E, Sanmartí GC, van Dongen SFM, García Rodríguez CL, Dolbnya IP, et al. Structure–delivery relationships of lysine-based Gemini surfactants and their lipoplexes. Soft Matter. 2014;10(31):5702-5714
  38. 38. Kwaśniewska D, Staszak K, Wieczorek D, Zieliński R. Synthesis and Interfacial Activity of Novel Heterogemini Sulfobetaines in Aqueous Solution. Journal of Surfactants and Detergents. 2015 May;18(3):477-486
  39. 39. Wang L, Zhang Y, Ding L, Liu J, Zhao B, Deng Q, et al. Synthesis and physiochemical properties of novel Gemini surfactants with phenyl-1,4-bis(carbamoylmethyl) spacer. RSC Advances. 2015;5(91):74764-74773
  40. 40. Badea I, Poorghorban M, Das U, Alaidi O, Chitanda J, Michel D, et al. Characterization of the host-guest complex of a curcumin analog with β-cyclodextrin and β-cyclodextrin-gemini surfactant and evaluation of its anticancer activity. International Journal of Nanomedicine. 2015 Jan;503
  41. 41. Ilies MA, Seitz WA, Johnson BH, Ezell EL, Miller AL, Thompson EB, et al. Lipophilic pyrylium salts in the synthesis of efficient pyridinium-based cationic lipids, Gemini surfactants, and lipophilic oligomers for gene delivery. Journal of Medicinal Chemistry. 2006 Jun;49(13):3872-3887
  42. 42. Kateb ME, Givenchy ET, Baklouti A, Guittard F. Synthesis and surface properties of semi-fluorinated Gemini surfactants with two reactive bromo pendant groups. Journal of Colloid and Interface Science. 2011 May;357(1):129-134
  43. 43. Jia W, Rao X, Song Z, Shang S. Microwave-assisted synthesis and properties of a novel cationic gemini surfactant with the hydrophenanthrene structure. Journal of Surfactants and Detergents. 2009 Aug;12(3):261-267
  44. 44. Tehrani-Bagha AR, Oskarsson H, van Ginkel CG, Holmberg K. Cationic ester-containing Gemini surfactants: Chemical hydrolysis and biodegradation. Journal of Colloid and Interface Science. 2007 Aug;312(2):444-452
  45. 45. Bunton CA, Robinson LB, Schaak J, Stam MF. Catalysis of nucleophilic substitutions by micelles of dicationic detergents. Journal of Organic Chemistry. 1971;36(16):2346-2350
  46. 46. Devinsky F, Masárová L, Lacko I. Surface activity and micelle formation of some new bisquaternary ammonium salts. Journal of Colloid and Interface Science. 1985;105(1):235-239
  47. 47. Zana R. Dimeric (Gemini) surfactants: Effect of the spacer group on the association behavior in aqueous solution. Journal of Colloid and Interface Science. 2002 Apr;248(2):203-220
  48. 48. Esumi K, Taguma K, Koide Y. Aqueous properties of multichain quaternary cationic surfactants. Langmuir. 1996;12(16):4039-4041
  49. 49. Zhu Y, Masuyama A, Okahara M. Preparation and surface active properties of amphipathic compounds with two sulfate groups and two lipophilic alkyl chains. Journal of the American Oil Chemists' Society. 1990;67(7):459-463
  50. 50. Zana R, Benrraou M, Rueff R. Alkanediyl-. alpha.,. omega.-bis (dimethylalkylammonium bromide) surfactants. 1. Effect of the spacer chain length on the critical micelle concentration and micelle ionization degree. Langmuir. 1991;7(6):1072-1075
  51. 51. De S, Aswal VK, Goyal PS, Bhattacharya S. Novel gemini micelles from dimeric surfactants with oxyethylene spacer chain. Small angle neutron scattering and fluorescence studies. Journal of Physical Chemistry. 1998;102:6152-6160
  52. 52. Lu T, Huang J. Synthesis and properties of novel gemini surfactant with short spacer. Chinese Science Bulletin. 2007 Oct;52(19):2618-2620
  53. 53. Brycki B, Drgas M, Bielawska M, Zdziennicka A, Jańczuk B. Synthesis, spectroscopic studies, aggregation and surface behavior of hexamethylene-1,6-bis(N,N-dimethyl-N-dodecylammonium bromide). Journal of Molecular Liquids 2016 Sep;221:1086-1096
  54. 54. Liao B, Li Y, Li Y. Synthesis of alpha- chloroacetates of ethylene glycol and its oligomers. Acta Polymerica Sinica. 1992;1(2):34-41
  55. 55. Gao Z, Tai S, Zhang Q, Zhao Y, Lu B, Ge Y, et al. Synthesis and surface activity of bisquaternary ammonium salt Gemini surfactants with ester bond. Wuhan University Journal of Natural Sciences. 2008;13(2):227-231
  56. 56. Łuczyński J, Frąckowiak R, Włoch A, Kleszczyńska H, Witek S. Gemini ester quat surfactants and their biological activity. Cellular and Molecular Biology Letters [Internet]. 2013 Jan 1 [cited 2017 Jan 20];18(1). Available from:
  57. 57. Morán MC, Pinazo A, Pérez L, Clapés P, Angelet M, García MT, et al. “Green” amino acid-based surfactants. Green Chemistry 2004;6(5):233-240
  58. 58. Goreti Silva S, Fernandes RF, Marques EF, do Vale MLC. Serine-based bis-quat Gemini surfactants: Synthesis and micellization properties. European Journal of Organic Chemistry. 2012 Jan;2012(2):345-352
  59. 59. Clapés P, Rosa Infante M. Amino acid-based surfactants: Enzymatic synthesis, Properties and Potential Applications. Biocatalysis and Biotransformation. 2002 Jan;20(4):215-233
  60. 60. Colomer A, Pinazo A, Manresa MA, Vinardell MP, Mitjans M, Infante MR, et al. Cationic surfactants derived from lysine: Effects of their structure and charge type on antimicrobial and hemolytic activities. Journal of Medicinal Chemistry. 2011 Feb 24;54(4):989-1002
  61. 61. Tan H, Xiao H. Synthesis and antimicrobial characterization of novel l-lysine Gemini surfactants pended with reactive groups. Tetrahedron Letters. 2008 Mar;49(11): 1759-1761
  62. 62. Gomes P, Araújo MJ, Marques EF, Falcão S, Brito RO. Straightforward method for the preparation of lysine-based double-chained anionic surfactants. Synthetic Communications. 2008 May 23;38(12):2025-2036
  63. 63. Yoshimura T, Sakato A, Tsuchiya K, Ohkubo T, Sakai H, Abe M, et al. Adsorption and aggregation properties of amino acid-based N-alkyl cysteine monomeric and -dialkyl cystine Gemini surfactants. Journal of Colloid and Interface Science. 2007 Apr;308(2):466-473
  64. 64. Seredyuk V, Alami E, Nyden M, Holmberg K, Peresypkin AV, Menger FM. Adsorption of zwitterionic Gemini surfactants at the air–water and solid–water interfaces. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2002;203(1):245-258
  65. 65. Peresypkin AV, Menger FM. Zwitterionic geminis. Coacervate formation from a single organic compound. Organic Letters. 1999 Nov;1(9):1347-1350
  66. 66. Yoshimura T, Ichinokawa T, Kaji M, Esumi K. Synthesis and surface-active properties of sulfobetaine-type zwitterionic Gemini surfactants. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2006 Feb;273(1–3):208-212
  67. 67. Yoshimura T, Nyuta K, Esumi K. Zwitterionic heterogemini surfactants containing ammonium and carboxylate headgroups. 1. Adsorption and micellization. Langmuir. 2005;21(7):2682-2688
  68. 68. Xie Z, Feng Y. Synthesis and properties of alkylbetaine zwitterionic Gemini surfactants. Journal of Surfactants and Detergents. 2010 Jan;13(1):51-57
  69. 69. Quagliotto P, Viscardi G, Barolo C, Barni E, Bellinvia S, Fisicaro E, et al. Gemini pyridinium surfactants: Synthesis and conductometric study of a novel class of amphiphiles. Journal of Organic Chemistry. 2003 Oct;68(20):7651-7660
  70. 70. Zhou L, Jiang X, Li Y, Chen Z, Hu X. Synthesis and properties of a novel class of gemini pyridinium surfactants. Langmuir. 2007 Nov;23(23):11404-11408
  71. 71. Shi L, Lundberg D, Musaev DG, Menger FM. Annulene Gemini surfactants: Structure and self-assembly. Angewandte Chemie, International Edition. 2007 Aug 3;46(31):5889-5891
  72. 72. Yamaguchi I, Gobara Y, Sato M. One-pot synthesis of N-substituted diaza[12] annulenes. Organic Letters. 2006 Sep;8(19):4279-4281.
  73. 73. Alami EO, Holmberg K. HeteroGemini surfactants. Advances in Colloid and Interface Science 2003;100:13-46
  74. 74. Jaeger DA, Li B, Clark TJ. Cleavable double-chain surfactants with one cationic and one anionic head group that form vesicles. Langmuir 1996;12:4314-4316
  75. 75. Xu Q, Wang L, Xing F. Synthesis and properties of dissymmetric Gemini surfactants. Journal of Surfactants and Detergents. 2011 Jan;14(1):85-90
  76. 76. Muslim AA, Ayyash D, Gujral SS, Mekhail GM, Rao PPN, Wettig SD. Synthesis and characterization of asymmetrical Gemini surfactants. Physical Chemistry Chemical Physics. 2017;19(3):1953-1962
  77. 77. Horikoshi S, Matsuzaki S, Mitani T, Serpone N. Microwave frequency effects on dielectric properties of some common solvents and on microwave-assisted syntheses: 2-Allylphenol and the C12–C2–C12 Gemini surfactant. Radiation Physics and Chemistry. 2012 Dec;81(12):1885-1895
  78. 78. Brycki B, Kowalczyk I, Kozirog A. Synthesis, molecular structure, spectral properties and antifungal activity of polymethylene-α,ω-bis(N,N- dimethyl-N-dodecylammonium bromides). Molecules. 2011 Jan 5;16(12):319-335
  79. 79. Chen L, Xie H, Li Y, Yu W. Applications of cationic gemini surfactant in preparing multi-walled carbon nanotube contained nanofluids. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2008 Dec;330(2–3):176-179
  80. 80. Landry JM, Marangoni DG, Lumsden MD, Berno R. 1D and 2D NMR investigations of the micelle-formation process in 8-phenyloctanoate micelles. Canadian Journal of Chemistry 2007;85:202-207
  81. 81. Wuthrich KI. Nmr of Proteins and Nucleic Acids. New York, USA: Wiley VCH; 1986.
  82. 82. Roscigno P, Asaro F, Pellizer G, Ortona O, Paduano L. Complex formation between poly (vinylpyrrolidone) and sodium decyl sulfate studied through NMR. Langmuir. 2003;19(23):9638-9644
  83. 83. Han P, He Y, Chen C, Yu H, Liu F, Yang H, et al. Study on synergistic mechanism of inhibitor mixture based on electron transfer behavior. Scientific Reports 2016 Sep 27;6:33252
  84. 84. Mobin M, Aslam R, Zehra S, Ahmad M. Bio-/environment-friendly cationic gemini surfactant as novel corrosion inhibitor for mild steel in 1 M HCl solution. Journal of Surfactants and Detergents. 2017 Jan;20(1):57-74
  85. 85. Yoshimura T, Nagata Y, Esumi K. Interactions of quaternary ammonium salt-type Gemini surfactants with sodium poly(styrene sulfonate). Journal of Colloid and Interface Science. 2004 Jul;275(2):618-622
  86. 86. Buse J, Badea I, Verrall RE, El-Aneed A. Tandem mass spectrometric analysis of the novel gemini surfactant nanoparticle families G12-s and G18:1-s. Spectroscopy Letters. 2010 Aug 17;43(6):447-457
  87. 87. Aimé C, Plet B, Manet S, Schmitter JM, Huc I, Oda R, et al. Competing gas-phase substitution and elimination reactions of Gemini surfactants with anionic counterions by mass spectrometry. Density functional theory correlations with their bolaform halide salt models. Journal of Physical Chemistry B. 2008 Nov 20;112(46):14435-14445
  88. 88. Wang S, Zhao K. Dielectric analysis for the spherical and rodlike micelle aggregates formed from a gemini surfactant: Driving forces of micellization and stability of micelles. Langmuir. 2016 Aug 2;32(30):7530-7540
  89. 89. Wilkes AJ, Waraven G, Talbot JM. HPLC analysis of quaternary ammonium surfactants with the evaporative light scattering detector. JAOCS. 1992;69(7)
  90. 90. Schmidtchen FP, Oswald H. RP-HPLC separation of highly charged quaternary ammonium salts. Journal of Liquid Chromatography. 1986 Apr;9(5):993-1002
  91. 91. Chen H, Wang C, Ye J, Zhou H, Lu L, Yang Z. Synthesis and properties of a lacquer wax-based quaternary ammonium gemini surfactant. Molecules. 2014 Mar 24;19(3):3596-3606
  92. 92. Wee VT, Kennedy JM. Determination of trace levels of quaternary ammonium compounds in river water by liquid chromatography with conductometric detection. Analytical Chemistry. 1982;54(9):1631-1633
  93. 93. Prince SJ, McLaury HJ, Allen LV, McLaury P. Analysis of benzalkonium chloride and its homologs: HPLC versus HPCE. Journal of Pharmaceutical and Biomedical Analysis. 1999;19(6):877-882
  94. 94. Vincent G, Kopferschmitt-Kubler MC, Mirabel P, Pauli G, Millet M. Sampling and analysis of quaternary ammonium compounds (QACs) traces in indoor atmosphere. Environmental Monitoring and Assessment. 2007 Oct;133(1–3):25-30
  95. 95. Epton SR. A rapid method of analysis for certain surface-active agents. Nature. 1947;6(4075):795-796
  96. 96. ASTM International D1681-05. Standart Test Method for Synthetic Anionic Active Ingredient in Detergents by Cationic Titration Procedure. ASTM International; West Conshohocken, USA, 2005
  97. 97. ASTM International D3049-89. Standard Test Method for Synthetic Anionic Ingredient by Cationic Titration. ASTM International; West Conshohocken, USA, 2003
  98. 98. BS 3762-3.1:1990, ISO 2271. Analysis of Formulated Detergents. Quantitative Test Methods. Method for Determination of Anionic-Active Matter Content. BSI; London, United Kingdom, 1989
  99. 99. DIN 38409-23:2010-12. German Standard Methods for the Examination of Water, Waste Water and Sludge—Parameters Characterizing Effects and Substances (Group H)—Part 23: Determination of Bismuth Active Substances (H 23). Berlin, Germany, 2010
  100. 100. Dietrich O. Handbook of Surfactant Analysis. London, United Kingdom: John Wiley & Sons; 2000
  101. 101. Rosen MJ, Kunjappu JJ. Surfactants and Interfacial Phenomena. 4th ed. New Jersy: John Wiley & Sons Interscience; 2012
  102. 102. Lai L, Mei P, Wu XM, Chen L, Liu Y. Interfacial dynamic properties and dilational rheology of mixed anionic and cationic Gemini surfactant systems at air–water interface. Colloids and Surfaces A: Physicochemical and Engineering Aspects 2016 Nov;509:341-350
  103. 103. Menger FM, Keiper JS, Azov V. Gemini Surfactants with Acetylenic Spacers. Langmuir. 2000 Mar;16(5):2062-2067
  104. 104. Garcia MT, Campos E, Sanchez-Leal J, Comelles F. Structure-activity relationships for sorption of alkyl trimethyl ammonium compounds on activated sludge. Tenside, Surfactants, Detergents. 2004;41(5):235-239
  105. 105. Hajy Alimohammadi M, Javadian S, Gharibi H, Tehrani-Bagha AR, Alavijeh MR, Kakaei K. Aggregation behavior and intermicellar interactions of cationic Gemini surfactants: Effects of alkyl chain, spacer lengths and temperature. Journal of Chemical Thermodynamics. 2012 Jan;44(1):107-115
  106. 106. Singh V, Tyagi R. Unique micellization and CMC aspects of Gemini surfactant: An overview. Journal of Dispersion Science and Technology. 2014 Nov 2;35(12):1774-1792
  107. 107. Laschewsky A, Wattebled L, Arotçaréna M, Habib-Jiwan JL, Rakotoaly RH. Synthesis and properties of cationic oligomeric surfactants. Langmuir. 2005;21(16):7170-7179
  108. 108. Yoshimura T, Chiba N, Matsuoka K. Supra-long chain surfactants with double or triple quaternary ammonium headgroups. Journal of Colloid and Interface Science. 2012 May;374(1):157-163
  109. 109. In M, Bec V, Aguerre-Chariol O, Zana R. Quaternary ammonium bromide surfactant oligomers in aqueous solution: Self-association and microstructure. Langmuir. 2000 Jan;16(1):141-148
  110. 110. Zana R. Alkanediyl-α,ω-bis(dimethylalkylammonium bromide) surfactants. Journal of Colloid and Interface Science. 2002 Feb;246(1):182-190
  111. 111. Wettig SD, Verrall RE. Thermodynamic studies of aqueous m–s–m Gemini surfactant systems. Journal of Colloid and Interface Science. 2001 Mar;235(2):310-316
  112. 112. Verma SK, Ghosh KK. Micellar and surface properties of some monomeric surfactants and a Gemini cationic surfactant. Journal of Surfactants and Detergents. 2011 Jul;14(3):347-352
  113. 113. Grosmaire L, Chorro M, Chorro C, Partyka S, Zana R. Alkanediyl-α,ω-bis(dimethylalkylammonium bromide) surfactants. Journal of Colloid and Interface Science. 2002 Feb;246(1):175-181
  114. 114. Wang X, Wang J, Wang Y, Yan H, Li P, Thomas RK. Effect of the nature of the spacer on the aggregation properties of Gemini surfactants in an aqueous solution. Langmuir. 2004 Jan;20(1):53-56
  115. 115. Menger FM, Keiper JS. Gemini surfactants. Angewandte Chemie, International Edition. 2000;39:1906-1920
  116. 116. Laschewsky A, Lunkenheimer K, Rakotoaly RH, Wattebled L. Spacer effects in dimeric cationic surfactants. Colloid & Polymer Science. 2005 Feb;283(5):469-479
  117. 117. Zhang Z, Wang H, Zheng P, Shen W. Effect of spacer rigidity on the aggregations of ester containing Gemini surfactants in aqueous solutions: A study of density and fluorescence. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2013 Mar;421:193-200
  118. 118. Teresa Garcia M, Kaczerewska O, Ribosa I, Brycki B, Materna P, Drgas M. Hydrophilicity and flexibility of the spacer as critical parameters on the aggregation behavior of long alkyl chain cationic gemini surfactants in aqueous solution. Journal of Molecular Liquids [Internet]. 2017 Jan [cited 2017 Jan 20]; Available from:
  119. 119. Zhang Q, Gao Z, Xu F, Tai S. Effect of hydrocarbon structure of the headgroup on the thermodynamic properties of micellization of cationic gemini surfactants: An electrical conductivity study. Journal of Colloid and Interface Science. 2012 Apr;371(1):73-81
  120. 120. Li B, Zhang Q, Xia Y, Gao Z. Surface properties and aggregation behavior of cationic gemini surfactants with dipropylammonium head-groups. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2015 Apr;470:211-217
  121. 121. Borse MS, Devi S. Importance of head group polarity in controlling aggregation properties of cationic gemini surfactants. Advances in Colloid and Interface Science. 2006 Nov;123–126:387-399
  122. 122. Kumar B, Tikariha D, Ghosh KK, Barbero N, Quagliotto P. Effect of polymers and temperature on critical micelle concentration of some gemini and monomeric surfactants. Journal of Chemical Thermodynamics 2013 Jul;62:178-185
  123. 123. Borse M, Sharma V, Aswal VK, Pokhriyal NK, Joshi JV, Goyal PS, et al. Small angle neutron scattering and viscosity studies of micellar solutions of bis-cationic surfactants containing hydroxyethyl methyl quaternary ammonium head groups. Physical Chemistry Chemical Physics. 2004;6(13):3508
  124. 124. Pisárčik M, Jampílek J, Devínsky F, Drábiková J, Tkacz J, Opravil T. Gemini surfactants with polymethylene spacer: Supramolecular structures at solid surface and aggregation in aqueous solution. Journal of Surfactants and Detergents. 2016 May;19(3):477-486
  125. 125. Tawfik SM, Abd-Elaal AA, Shaban SM, Roshdy AA. Surface, thermodynamic and biological activities of some synthesized Gemini quaternary ammonium salts based on polyethylene glycol. Journal of Industrial and Engineering Chemistry. 2015 Oct;30:112-119
  126. 126. Zana R. Critical micellization concentration of surfactants in aqueous solution and free energy of micellization. Langmuir. 1996;12(5):1208-1211
  127. 127. Cornellas A, Perez L, Comelles F, Ribosa I, Manresa A, Garcia MT. Self-aggregation and antimicrobial activity of imidazolium and pyridinium based ionic liquids in aqueous solution. Journal of Colloid and Interface Science. 2011 Mar;355(1):164-171
  128. 128. Aiad I, El-Sukkary MM, Soliman EA, El-Awady MY, Shaban SM. Characterization, surface properties and biological activity of new prepared cationic surfactants. Journal of Industrial and Engineering Chemistry. 2014 Jul;20(4):1633-1640
  129. 129. Block SS. Disinfection, Sterilization and Preservations 5th ed. Philadelphia: Lippincott Williams & Wilkins; 2001
  130. 130. Manivannan G. Disinfection and Decontamination; Principles, Applications and Related Issues. Boca Raton USA: CRC Press Taylor & Francis Group; 2008
  131. 131. Paulus W. Directory of Microbiocides for the Protection of Material. A Handbook. Dordrecht, The Netherlands: Springer; 2005
  132. 132. Cross J, Singer J. Cationic Surfactants, Analytical and Biological Evaluation. New York, USA: Marcel Dekker; 1994
  133. 133. Lambert PA. Mechanisms of action of microbicides. In: Principles and Practise of Disinfection, Preservation, and Sterilization. 5th ed. Chichester, West Sussex: John Wiley & Sons; 2012
  134. 134. Millard JS. Mechanisms of bacterial resistance to microbicides. In: Principles and Practice of Disinfection, Preservation and Sterilization. 5th ed. Chichester, West Sussex: John Wiley & Sons; 2012
  135. 135. Chapman JS. Biocide resistance mechanisms. International Biodeterioration and Biodegradation. 2003;51(2):133-138
  136. 136. Brycki B, Szulc A. Gemini alkyldeoxy-D-glucitolammonium salts as modern surfactants and microbiocides: Synthesis, antimicrobial and surface activity, biodegradation. Johnson SJ, editor. PLoS ONE. 2014 Jan 8;9(1):e84936
  137. 137. Zhang S, Ding S, Yu J, Chen X, Lei Q, Fang W. Antibacterial activity, in vitro cytotoxicity, and cell cycle arrest of Gemini quaternary ammonium surfactants. Langmuir. 2015 Nov 10;31(44):12161-12169
  138. 138. Brycki B. Gemini alkylammonium salts as biodeterioration inhibitors. Polish Journal of Microbiology. 2010;59:227-231
  139. 139. Russell AD. Biocide use and antibiotic resistance: the relevance of laboratory findings to clinical and environmental situations. Lancet Infectious Diseases. 2003;3(12):794-803
  140. 140. Jorgensen JH, Ferraro MJ. Antimicrobial susceptibility testing: A review of general principles and contemporary practices. Clinical Infectious Diseases. 2009 Dec;49(11):1749-1755
  141. 141. Tyagi S, Tyagi VK. Novel cationic Gemini surfactants and methods for determination of their antimicrobial activity–review. Tenside, Surfactants, Detergents. 2014;51:379-386
  142. 142. Klančnik A, Piskernik S, Jeršek B, Možina SS. Evaluation of diffusion and dilution methods to determine the antibacterial activity of plant extracts. Journal of Microbiological Methods. 2010 May;81(2):121-126
  143. 143. Kuperkar K, Modi J, Patel K. Surface-active properties and antimicrobial study of conventional cationic and synthesized symmetrical Gemini surfactants. Journal of Surfactants and Detergents. 2012 Jan;15(1):107-115
  144. 144. Koziróg A, Brycki B. Monomeric and gemini surfactants as antimicrobial agents—influence on environmental and reference strains. Acta Biochimica Polonica. 2015;62(4):879-883
  145. 145. Paniak TJ, Jennings MC, Shanahan PC, Joyce MD, Santiago CN, Wuest WM, et al. The antimicrobial activity of mono-, bis-, tris-, and tetracationic amphiphiles derived from simple polyamine platforms. Bioorganic & Medicinal Chemistry Letters. 2014 Dec;24(24):5824-5828
  146. 146. Black JW, Jennings MC, Azarewicz J, Paniak TJ, Grenier MC, Wuest WM, et al. TMEDA-derived biscationic amphiphiles: An economical preparation of potent antibacterial agents. Bioorganic & Medicinal Chemistry Letters. 2014 Jan;24(1):99-102
  147. 147. Laatiris A, El Achouri M, Rosa Infante M, Bensouda Y. Antibacterial activity, structure and CMC relationships of alkanediyl α,ω-bis(dimethylammonium bromide) surfactants. Microbiological Research. 2008 Nov;163(6):645-650
  148. 148. Banno T, Toshima K, Kawada K, Matsumura S. Synthesis and properties of Gemini-type cationic surfactants containing carbonate linkages in the linker moiety directed toward green and sustainable chemistry. Journal of Surfactants and Detergents. 2009 Aug;12(3):249-259
  149. 149. Tatsumi T, Zhang W, Nakatsuji Y, Miyake K, Matsushima K, Tanaka M, et al. Preparation, surface-active properties, and antimicrobial activities of bis (alkylammonium) dichlorides having a butenylen or a butynylene spacer. Journal of Surfactants and Detergents. 2001;4(3):271-277
  150. 150. Martín VI, de la Haba RR, Ventosa A, Congiu E, Ortega-Calvo JJ, Moyá ML. Colloidal and biological properties of cationic single-chain and dimeric surfactants. Colloids and Surfaces. B, Biointerfaces. 2014 Feb;114:247-254
  151. 151. Hansch C, Fujita T. p-σ-π Analysis. A method for the correlation of biological activity and chemical structure. Journal of the American Chemical Society. 1964;86(8):1616-1626
  152. 152. Hansch C, Clayton JM. Lipophilic character and biological activity of drugs II: The parabolic case. Journal of Pharmaceutical Sciences. 1973;62(1):1-21
  153. 153. Fatma N, Panda M, Kabir-ud D, Beg M. Ester-bonded cationic gemini surfactants: Assessment of their cytotoxicity and antimicrobial activity. Journal of Molecular Liquids. 2016 Oct;222:390-394
  154. 154. Guo S, Sun X, Zou Q, Zhang J, Ni H. Antibacterial activities of five cationic Gemini surfactants with ethylene glycol bisacetyl spacers. Journal of Surfactants and Detergents. 2014 Nov;17(6):1089-1097
  155. 155. Zhu H, Hu Z, Ma X, Wang J, Cao D. Synthesis, surface and antimicrobial activities of cationic Gemini surfactants with semi-rigid spacers. Journal of Surfactants and Detergents. 2016 Mar;19(2):265-274.
  156. 156. Li H, Yu C, Chen R, Li J, Li J. Novel ionic liquid-type Gemini surfactants: Synthesis, surface property and antimicrobial activity. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2012 Feb;395:116-124
  157. 157. Diz M, Manresa A, Pinazo A, Erra P, Infante M. Synthesis, surface active properties and antimicrobial activity of new bis quaternary ammonium compounds. Journal of the Chemical Society, Perkin Transactions 2. 1994;(8):1871-1876
  158. 158. Murguía MC, Machuca LM, Lurá MC, Cabrera MI, Grau RJ. Synthesis and properties of novel antifungal Gemini compounds derived from N-acetyl diethanolamines. Journal of Surfactants and Detergents. 2008 Sep;11(3):223-230
  159. 159. Labena A, Hegazy MA, Horn H, Müller E. Cationic Gemini surfactant as a corrosion inhibitor and a biocide for high salinity sulfidogenic bacteria originating from an oil-field water tank. Journal of Surfactants and Detergents. 2014 May;17(3):419-431
  160. 160. Obłąk E, Piecuch A, Krasowska A, Łuczyński J. Antifungal activity of gemini quaternary ammonium salts. Microbiological Research. 2013 Dec;168(10):630-638
  161. 161. Obłąk E, Piecuch A, Guz-Regner K, Dworniczek E. Antibacterial activity of gemini quaternary ammonium salts. FEMS Microbiology Letters. 2014 Jan;350(2):190-198
  162. 162. Obłąk E, Piecuch A, Dworniczek E, Olejniczak T. The influence of biodegradable gemini surfactants, N,N’-bis(1-decyloxy-1-oxypronan-2-yl)-N,N,N’,N’-tetramethylpropane-1,3-diammonium dibromide and N,N’-bis(1-dodecyloxy-1-oxopronan-2-yl)-N,N,N’,N’-tetramethane-1,2-diammonium dibromide, on fungal biofilm and adhesion. Journal of Oleo Science. 2015;64:527-537
  163. 163. Badr EE, Kandeel EM, El-Sadek BM. Novel gemini cationic surfactants based on N,N-dimethyl fatty hydrazine and 1,3-dibromopropane; synthesis, mechanism of action, and cytotoxicities. Journal of Oleo Science 2010;59:647-652
  164. 164. Hoque J, Akkapeddi P, Yarlagadda V, Uppu DSSM, Kumar P, Haldar J. Cleavable cationic antibacterial amphiphiles: Synthesis, mechanism of action, and cytotoxicities. Langmuir. 2012 Aug 21;28(33):12225-12234
  165. 165. Ghumare AK, Pawar BV, Bhagwat SS. Synthesis and antibacterial activity of novel amido-amine-based cationic Gemini surfactants. Journal of Surfactants and Detergents. 2013 Jan;16(1):85-93
  166. 166. Banno T, Kawada K, Matsumura S. Creation of novel green and sustainable Gemini-type cationics containing carbonate linkages. Journal of Surfactants and Detergents. 2010 Oct;13(4):387-398
  167. 167. Ding Z, Fang S. Synthesis, surface and antimicrobial activities of novel cationic Gemini surfactants. Journal of Surfactants and Detergents. 2015 Nov;18(6):1051-1057
  168. 168. Węgrzyńska J, Chlebicki J, Maliszewska I. Preparation, surface-active properties and antimicrobial activities of bis(ester quaternary ammonium) salts. Journal of Surfactants and Detergents. 2007 May 8;10(2):109-116
  169. 169. Caillier L, Taffin de Givenchy E, Levy R, Vandenberghe Y, Geribaldi S, Guittard F. Polymerizable semi-fluorinated gemini surfactants designed for antimicrobial materials. Journal of Colloid and Interface Science. 2009 Apr;332(1):201-207
  170. 170. Sharma V, Borse M, Devi S, Dave K, Pohnerkar J, Prajapati A. Oil solubilization capacity, liquid crystalline properties, and antibacterial activity of alkanolamine‐based novel cationic surfactants. Journal of Dispersion Science and Technology. 2005 Jul;26(4):421-427
  171. 171. Garcia MT, Kaczerewska O, Ribosa I, Brycki B, Materna P, Drgas M. Biodegradability and aquatic toxicity of quaternary ammonium-based gemini surfactants: Effect of the spacer on their ecological properties. Chemosphere 2016 Jul;154:155-160
  172. 172. Brycki B, Waligórska M, Szulc A. The biodegradation of monomeric and dimeric alkylammonium surfactants. Journal of Hazardous Materials. 2014 Sep;280:797-815
  173. 173. Colomer A, Pinazo A, García MT, Mitjans M, Vinardell MP, Infante MR, et al. pH-Sensitive surfactants from lysine: Assessment of their cytotoxicity and environmental behavior. Langmuir. 2012 Apr 10;28(14):5900-5912
  174. 174. Tehrani-Bagha AR, Holmberg K, van Ginkel CG, Kean M. Cationic gemini surfactants with cleavable spacer: Chemical hydrolysis, biodegradation, and toxicity. Journal of Colloid and Interface Science 2015 Jul;449:72-79
  175. 175. Tehrani-Bagha AR, Holmberg K. Cationic ester-containing Gemini surfactants: Physical–chemical properties. Langmuir. 2010 Jun 15;26(12):9276-9282
  176. 176. Tawfik SM, Abd-Elaal AA, Aiad I. Three gemini cationic surfactants as biodegradable corrosion inhibitors for carbon steel in HCl solution. Research on Chemical Intermediates. 2016 Feb;42(2):1101-1123
  177. 177. Akram M, Anwar S, Ansari F, Bhat IA, Kabir-ud D. Bio-physicochemical analysis of ethylene oxide-linked diester-functionalized green cationic gemini surfactants. RSC Advances. 2016;6(26):21697-21705
  178. 178. Akram M, Ansari F, Bhat IA, Chaturvedi SK, Khan RH, Kabir-ud D. An ester-functionalized cationic gemini surfactant mediated structural transitions of porcine serum albumin (PSA) via binding interaction. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2017 Mar;516:245-253
  179. 179. Bergero MF, Liffourrena AS, Opizzo BA, Fochesatto AS, Lucchesi GI. Immobilization of a microbial consortium on Ca-alginate enhances degradation of cationic surfactants in flasks and bioreactor. International Biodeterioration & Biodegradation 2017 Feb;117:39-44
  180. 180. Akram M, Bhat IA, Kabir-ud D. Effect of salt counterions on the physicochemical characteristics of novel green surfactant, ethane-1,2-diyl bis(N,N-dimethyl-N-tetradecylammoniumacetoxy) dichloride. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2016 Mar;493:32-40
  181. 181. Pérez L, Garcia MT, Ribosa I, Vinardell MP, Manresa A, Infante MR. Biological properties of arginine-based gemini cationic surfactants. Environmental Toxicology & Chemistry. 2002;21(6):1279-1285
  182. 182. Zhou F, Maeda T, Nagamune H, Kourai H. Synthesis and antimicrobial characteristics of novel biocides, 1, 1’-(decanedioyl) bis (4-methy1-4-alkylpiperazinium iodide) s with a Gemini structure. Biocontrol Science. 2004;9(3):61-67
  183. 183. Chauhan V, Singh S, Kaur T, Kaur G. Self-assembly and biophysical properties of Gemini 3-alkyloxypyridinium amphiphiles with a hydroxyl-substituted spacer. Langmuir. 2015 Mar 17;31(10):2956-2966
  184. 184. Almeida JAS, Faneca H, Carvalho RA, Marques EF, Pais AACC. Dicationic alkylammonium bromide Gemini surfactants. Membrane perturbation and skin irritation. Fraternali F, editor. PLoS ONE. 2011 Nov 10;6(11):e26965
  185. 185. Silva SMC, Sousa JJS, Marques EF, Pais AACC, Michniak-Kohn BB. Structure activity relationships in alkylammonium C12-Gemini surfactants used as dermal permeation enhancers. The AAPS Journal. 2013 Oct;15(4):1119-1127
  186. 186. McCafferty E. Introduction to Corrosion Science. Springer; London, United Kingdom, 2010. 575 p
  187. 187. Bardal E. Corrosion and Protection. London; New York: Springer; 2004. 315 p
  188. 188. Sastri VS, Ghali E, Elboujdaini M. Corrosion Prevention and Protection; Practical Solutions. England: John Wiley & Sons Ltd.; 2007
  189. 189. ASTM International. ASTM G15-02. Standard Terminology Relating to Corrosion and Corrosion Testing. ASTM International; West Conshohocken, USA, 2002.
  190. 190. Hegazy MA, Abd El-Rehim SS, Badr EA, Kamel WM, Youssif AH. Mono-, di- and tetra-cationic surfactants as carbon steel corrosion inhibitors. Journal of Surfactants and Detergents. 2015 Nov;18(6):1033–1042
  191. 191. Cao K, Sun HY, Hou BR. Corrosion inhibition of Gemini surfactant for copper in 3.5% NaCl. Advances in Materials Research. 2014 Jun;936:1125-1131
  192. 192. Asefi D, Arami M, Mahmoodi NM. Comparing chain length effect of single chain and Gemini surfactants on corrosion inhibition of steel in acid. ECS Transactions. 2011;35(17):89-101
  193. 193. Hegazy MA, El-Tabei AS. Synthesis, surface properties, synergism parameter and inhibitive performance of novel cationic Gemini surfactant on carbon steel corrosion in 1 M HCl solution. Journal of Surfactants and Detergents. 2013 Mar;16(2):221-232
  194. 194. Migahed MA, Rashwan SM, Kamel MM, Habib RE. Synthesis, characterization of polyaspartic acid-glycine adduct and evaluation of their performance as scale and corrosion inhibitor in desalination water plants. Journal of Molecular Liquids 2016 Dec;224:849-858
  195. 195. Hegazy MA, Rashwan SM, Kamel MM, El Kotb MS. Synthesis, surface properties and inhibition behavior of novel cationic gemini surfactant for corrosion of carbon steel tubes in acidic solution. Journal of Molecular Liquids 2015 Nov;211:126-134
  196. 196. Mobin M, Masroor S. Adsorption and corrosion inhibition behavior of schiff base-based cationic Gemini surfactant on mild steel in formic acid. Journal of Dispersion Science and Technology. 2014 Apr 3;35(4):535-543
  197. 197. Hegazy MA, El-Etre AY, El-Shafaie M, Berry KM. Novel cationic surfactants for corrosion inhibition of carbon steel pipelines in oil and gas wells applications. Journal of Molecular Liquids 2016 Feb;214:347-356
  198. 198. Aiad I, Riya MA, Tawfik SM, Abousehly MA. Protection of carbon steel against corrosion in hydrochloric acid solution by some synthesized cationic surfactants. Protection of Metals and Physical Chemistry of Surfaces. 2016 Mar;52(2):339-347
  199. 199. Mobin M, Masroor S. Cationic gemini surfactants as novel corrosion inhibitor for mild steel in 1M HCl. International Journal of Electrochemical Science. 2012;7:6920-6940
  200. 200. Zhang Q, Gao Z, Xu F, Zou X. Adsorption and corrosion inhibitive properties of gemini surfactants in the series of hexanediyl-1,6-bis-(diethyl alkyl ammonium bromide) on aluminium in hydrochloric acid solution. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2011 May;380(1–3):191-200
  201. 201. Ash M, Ash I. Handbook of Corrosion Inhibitors [Internet]. Endicott, N.Y.: Synapse Information Resources; 2011 [cited 2017 Jan 20]. Available from:
  202. 202. von Baeckmann W, Schwenk W, Prinz W, von Baeckmann W, editors. Handbook of Cathodic Corrosion Protection: Theory and Practice of Electrochemical Protection Processes. 3rd ed. Houston, Tex: Gulf Pub. Co; 1997. 567 p
  203. 203. Grundmeier G, Schmidt W, Stratmann M. Corrosion protection by organic coatings: electrochemical mechanism and novel methods of investigation. Electrochimica Acta. 2000;45(15):2515-2533
  204. 204. Riggs OL, Locke CE, Hamner NE. Anodic Protection Theory and Practice in the Prevention of Corrosion. Boston, MA: Springer US; 1981
  205. 205. Wojciechowski J, Szubert K, Peipmann R, Fritz M, Schmidt U, Bund A, et al. Anti-corrosive properties of silane coatings deposited on anodised aluminium. Electrochimica Acta 2016 Dec;220:1-10
  206. 206. Sun YM, Chen HL. A study of corrosion inhibition of carbon steel in hydrochloric acid using BIMGCS12-3. Advances in Materials Research. 2012 Jan;427:3-6
  207. 207. Hegazy MA, Azzam EMS, Kandil NG, Badawi AM, Sami RM. Corrosion inhibition of carbon steel pipelines by some new amphoteric and di-cationic surfactants in acidic solution by chemical and electrochemical methods. Journal of Surfactants and Detergents. 2016 Jul;19(4):861-871
  208. 208. Abdallah M, Eltass HM, Hegazy MA, Ahmed H. Adsorption and inhibition effect of novel cationic surfactant for pipelines carbon steel in acidic solution. Protection of Metals and Physical Chemistry of Surfaces. 2016 Jul;52(4):721-730
  209. 209. Hegazy MA, Abdallah M, Awad MK, Rezk M. Three novel di-quaternary ammonium salts as corrosion inhibitors for API X65 steel pipeline in acidic solution. Part I: Experimental results. Corrosion Science. 2014 Apr;81:54-64
  210. 210. Hegazy MA, Atlam FM. Three novel bolaamphiphiles as corrosion inhibitors for carbon steel in hydrochloric acid: Experimental and computational studies. Journal of Molecular Liquids. 2016 Jun;218:649-662
  211. 211. Mahdavian M, Tehrani-Bagha AR, Holmberg K. Comparison of a cationic Gemini surfactant and the corresponding monomeric surfactant for corrosion protection of mild steel in hydrochloric acid. Journal of Surfactants and Detergents. 2011 Oct;14(4):605-613
  212. 212. Nessim IM, Hamdy A, Osman MM, Shalaby MN. Inhibitory effect of some cationic Gemini surfactants for carbon steel in sea water. International Journal of Chemistry. 2012;02.
  213. 213. Mobin M, Masroor S. Alkanediyl-α, ω-bis (dimethyl cetylammonium bromide) gemini surfactants as novel corrosion inhibitors for mild steel in formic acid. Materials Research. 2012 Dec;15(6):837-847
  214. 214. Qiu LG, Xie AJ, Shen YH. Understanding the effect of the spacer length on adsorption of gemini surfactants onto steel surface in acid medium. Applied Surface Science. 2005 Jun;246(1–3):1-5
  215. 215. Tawfik SM. Ionic liquids based gemini cationic surfactants as corrosion inhibitors for carbon steel in hydrochloric acid solution. Journal of Molecular Liquids. 2016 Apr;216:624-635
  216. 216. Migahed MA, Hegazy MA, Al-Sabagh AM. Synergistic inhibition effect between Cu2+ and cationic gemini surfactant on the corrosion of downhole tubing steel during secondary oil recovery of old wells. Corrosion Science. 2012 Aug;61:10-18
  217. 217. Qiu LG, Wu Y, Wang YM, Jiang X. Synergistic effect between cationic gemini surfactant and chloride ion for the corrosion inhibition of steel in sulphuric acid. Corrosion Science. 2008 Feb;50(2):576-582
  218. 218. Wu ZY, Fang Z, Qiu LG, Wu Y, Li ZQ, Xu T, et al. Synergistic inhibition between the gemini surfactant and bromide ion for steel corrosion in sulphuric acid. Journal of Applied Electrochemistry. 2009 Jun;39(6):779-784
  219. 219. Zhao J, Duan H, Jiang R. Synergistic corrosion inhibition effect of quinoline quaternary ammonium salt and Gemini surfactant in H2S and CO2 saturated brine solution. Corrosion Science 2015 Feb;91:108-119
  220. 220. Altamirano RH, Cervantes VYM, Rivera LSZ, Conde HIB, Ramirez SL. Gemini Surfactants, Process of Manufacture and Use as Multifunctional Corrosion Inhibitors. US 9023785 B2, 2015
  221. 221. Henry KM, Hicks KD. Bis-quaternary ammonium salt corrosion inhibitors. US 8999315 B2, 2015
  222. 222. Ahmed T, Kamel AO, Wettig SD. Interactions between DNA and Gemini surfactant: Impact on gene therapy: Part I. Nanomedicine. 2016 Feb;11(3):289-306
  223. 223. Pisárčik M, Devínsky F. Surface tension study of cationic gemini surfactants binding to DNA. Central European Journal of Chemistry. 2014 May;12(5):577-585
  224. 224. Geoffroy M, Faure D, Oda R, Bassani DM, Baigl D. Photocontrol of genomic DNA conformation by using a photosensitive Gemini surfactant: Binding affinity versus reversibility. ChemBioChem. 2008 Oct 13;9(15):2382-2385
  225. 225. Kirby AJ, Camilleri P, Engberts JBFN, Feiters MC, Nolte RJM, Söderman O, et al. Gemini surfactants: New synthetic vectors for gene transfection. Angewandte Chemie, International Edition. 2003 Apr 4;42(13):1448-1457
  226. 226. Al-Dulaymi MA, Chitanda JM, Mohammed-Saeid W, Araghi HY, Verrall RE, Grochulski P, et al. Di-peptide-modified Gemini surfactants as gene delivery vectors: Exploring the role of the alkyl tail in their physicochemical behavior and biological activity. The AAPS Journal. 2016 Sep;18(5):1168-1181
  227. 227. Kim BK. Synthesis and optimization of cholesterol-based diquaternary ammonium Gemini surfactant (Chol-GS) as a new gene delivery vector. Journal of Microbiology and Biotechnology. 2011;21(1):93-99
  228. 228. Zakharova LY, Gabdrakhmanov DR, Ibragimova AR, Vasilieva EA, Nizameev IR, Kadirov MK, et al. Structural, biocomplexation and gene delivery properties of hydroxyethylated gemini surfactants with varied spacer length. Colloids and Surfaces. B, Biointerfaces. 2016 Apr;140:269-277
  229. 229. Fisicaro E, Compari C, Bacciottini F, Contardi L, Pongiluppi E, Barbero N, et al. Nonviral gene-delivery by highly fluorinated gemini bispyridinium surfactant-based DNA nanoparticles. Journal of Colloid and Interface Science. 2017 Feb;487:182-191
  230. 230. McGregor C, Perrin C, Monck M, Camilleri P, Kirby AJ. Rational approaches to the design of cationic Gemini surfactants for gene delivery. Journal of the American Chemical Society. 2001 Jul;123(26):6215-6220
  231. 231. Camilleri P, Kremer A, Edwards AJ, Jennings KH, Jenkins O, Marshall I, et al. A novel class of cationic gemini surfactants showing efficient in vitro gene transfection properties. Chemical Communications. 2000;(14):1253-1254
  232. 232. Bazylińska U, Saczko J. Nanoemulsion-templated polyelectrolyte multifunctional nanocapsules for DNA entrapment and bioimaging. Colloids and Surfaces. B, Biointerfaces. 2016 Jan;137:191-202
  233. 233. Wang L, Zhang C, Xie H, Sun W, Chen X, Wang X, et al. Calcium alginate gel capsules loaded with inhibitor for corrosion protection of downhole tube in oilfields. Corrosion Science. 2015 Jan;90:296-304
  234. 234. Minkenberg CB, Li F, van Rijn P, Florusse L, Boekhoven J, Stuart MCA, et al. Responsive vesicles from dynamic covalent surfactants. Angewandte Chemie, International Edition. 2011 Apr 4;50(15):3421-3424
  235. 235. Minkenberg CB, Homan B, Boekhoven J, Norder B, Koper GJM, Eelkema R, et al. Responsive wormlike micelles from dynamic covalent surfactants. Langmuir. 2012 Sep 25;28(38):13570-13576
  236. 236. Feng Y, Chu Z. pH-Tunable wormlike micelles based on an ultra-long-chain “pseudo” gemini surfactant. Soft Matter. 2015;11(23):4614-4620
  237. 237. Wang X, Zhang Z, Cao Y, Hao J. Ionogels of pseudogemini supra-amphiphiles in ethylammonium nitrate: Structures and properties. Journal of Colloid and Interface Science. 2017 Apr;491:64-71
  238. 238. Akay G, Hassan-Raeisi A, Tuncaboylu DC, Orakdogen N, Abdurrahmanoglu S, Oppermann W, et al. Self-healing hydrogels formed in catanionic surfactant solutions. Soft Matter. 2013;9(7):2254
  239. 239. Menger FM, Peresypkin AV, Caran KL, Apkarian RP. A sponge morphology in an elementary coacervate. Langmuir. 2000 Nov;16(24):9113-9116
  240. 240. Lv J, Qiao W, Li Z. Vesicles from pH-regulated reversible gemini amino-acid surfactants as nanocapsules for delivery. Colloids and Surfaces. B, Biointerfaces. 2016 Oct;146:523-531
  241. 241. Mirgorodskaya AB, Ya Zakharova L, Khairutdinova EI, Lukashenko SS, Sinyashin OG. Supramolecular systems based on gemini surfactants for enhancing solubility of spectral probes and drugs in aqueous solution. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2016 Dec;510:33-42
  242. 242. Tiwari AK, Gangopadhyay S, Chang CH, Pande S, Saha SK. Study on metal nanoparticles synthesis and orientation of gemini surfactant molecules used as stabilizer. Journal of Colloid and Interface Science. 2015 May;445:76-83
  243. 243. Wang W, Han Y, Tian M, Fan Y, Tang Y, Gao M, et al. Cationic Gemini surfactant-assisted synthesis of hollow Au nanostructures by stepwise reductions. ACS Applied Materials & Interfaces. 2013 Jun 26;5(12):5709-5716
  244. 244. Xu Y, Zhao Y, Chen L, Wang X, Sun J, Wu H, et al. Large-scale, low-cost synthesis of monodispersed gold nanorods using a gemini surfactant. Nanoscale. 2015;7(15):6790-6797
  245. 245. Alejo T, Paulo PMR, Merchán MD, Garcia-Fernandez E, Costa SMB, Velázquez MM. Influence of 3D aggregation on the photoluminescence dynamics of CdSe quantum dot films. Journal of Luminescence. 2017 Mar;183:113-120
  246. 246. Jamwal D, Rana D, Singh P, Pathak D, Kalia S, Thakur P, et al. Well-defined quantum dots and broadening of optical phonon line from hydrothermal method. RSC Advances. 2016;6(104):102010-102014
  247. 247. Gaynanova GA, Vasilieva EA, Bekmukhametova AM, Nizameev IR, Kadirov MK, Zakharova LY, et al. Encapsulation of quantum dots in supramolecular systems based on amphiphilic compounds and polyelectrolytes. Russian Chemical Bulletin. 2016;65(1):151-157
  248. 248. Feizi N, Yamini Y, Moradi M, Karimi M, Salamat Q, Amanzadeh H. A new generation of nano-structured supramolecular solvents based on propanol/gemini surfactant for liquid phase microextraction. Analytica Chimica Acta. 2017 Feb;953:1-9
  249. 249. Wang Y, Guo R, Xi J. Comparative studies of interactions of hemoglobin with single-chain and with gemini surfactants. Journal of Colloid and Interface Science. 2009 Mar;331(2):470-475
  250. 250. Li Y, Wang X, Wang Y. Comparative studies on interactions of bovine serum albumin with cationic Gemini and single-chain surfactants. Journal of Physical Chemistry B. 2006 Apr;110(16):8499-8505
  251. 251. Ansari WH, Fatma N, Panda M, Kabir-ud D. Solubilization of polycyclic aromatic hydrocarbons by novel biodegradable cationic gemini surfactant ethane-1,2-diyl bis(N,N-dimethyl-N-hexadecylammoniumacetoxy) dichloride and its binary mixtures with conventional surfactants. Soft Matter. 2013;9(5):1478
  252. 252. Panda M, Kabir-ud D. Study of surface and solution properties of gemini-conventional surfactant mixtures and their effects on solubilization of polycyclic aromatic hydrocarbons. Journal of Molecular Liquids. 2011 Sep;163(2):93-98
  253. 253. Siddiqui H, Kamil M, Panda M, Kabir-ud D. Solubilization of phenanthrene and fluorene in equimolar binary mixtures of Gemini/conventional surfactants. Chinese Journal of Chemical Engineering. 2014 Sep;22(9):1009-1015
  254. 254. Siddiqui H, Kamil M, Nazish F. Surface and solution properties of single and mixed gemini/conventional micelles on solubilization of polycyclic aromatic hydrocarbons. Indian Journal of Chemical Technology. 2015;22:194-200
  255. 255. Tehrani-Bagha AR, Singh RG, Holmberg K. Solubilization of two organic dyes by cationic ester-containing gemini surfactants. Journal of Colloid and Interface Science. 2012 Jun;376(1):112-118
  256. 256. Gharanjig K, Sadeghi-Kiakhani M, Tehrani-Bagha AR, Khosravi A, Menger FM. Solubility of two disperse dyes derived from N-alkyl and N-carboxylic acid naphthalimides in the presence of Gemini cationic surfactants. Journal of Surfactants and Detergents. 2011 Jul;14(3):381-389
  257. 257. Lakra J, Tikariha D, Yadav T, Das S, Ghosh S, Satnami ML, et al. Mixed micellization of gemini and cationic surfactants: Physicochemical properties and solubilization of polycyclic aromatic hydrocarbons. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2014 Jun;451:56-65
  258. 258. Wei J, Huang G, An C, Yu H. Investigation on the solubilization of polycyclic aromatic hydrocarbons in the presence of single and mixed Gemini surfactants. Journal of Hazardous Materials. 2011 Jun;190(1–3):840-847
  259. 259. Wei J, Huang G, Wang S, Zhao S, Yao Y. Improved solubilities of PAHs by multi-component Gemini surfactant systems with different spacer lengths. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2013 Apr;423:50-57
  260. 260. Silva PR, Almeida VO, Machado GB, Benvenutti EV, Costa TMH, Gallas MR. Surfactant-based dispersant for multiwall carbon nanotubes to prepare ceramic composites by a sol–gel method. Langmuir. 2012 Jan 17;28(2):1447-1452
  261. 261. Di Crescenzo A, Cambré S, Germani R, Di Profio P, Fontana A. Dispersion of SWCNTs with imidazolium-rich surfactants. Langmuir. 2014 Apr 15;30(14):3979-3987
  262. 262. Poorgholami-Bejarpasi N, Sohrabi B. Role of surfactant structure in aqueous dispersions of carbon nanotubes. Fluid Phase Equilibria 2015 May;394:19-28
  263. 263. Zhang S, Lu F, Zheng L. Dispersion of multiwalled carbon nanotubes (MWCNTs) by ionic liquid-based Gemini pyrrolidinium surfactants in aqueous solution. Colloid & Polymer Science. 2011 Nov;289(17–18):1815-1819
  264. 264. Li D, Fang W, Wang H, Gao C, Zhang R, Cai K. Gold/oil nanofluids stabilized by a Gemini surfactant and their catalytic property. Industrial & Engineering Chemistry Research. 2013 Jun 19;52(24):8109-8113
  265. 265. Xu J, Han X, Liu H, Hu Y. Synthesis of monodisperse gold nanoparticles stabilized by Gemini surfactant in reverse micelles. Journal of Dispersion Science and Technology. 2005 Jul;26(4):473-476
  266. 266. Bi S, Peng H, Liao Y, Yang Y, Brycki B, Xie X. Microstructure and performances of pva dispersed liquid crystals containing gemini surfactant. Acta Polymerica Sinica. 2012;16(6):628-632
  267. 267. Wang H, He L, Brycki BE, Kowalczyk IH, Kuliszewska E, Yang Y. Electrochemical characterization of the hydrophobic microenvironment with gemini surfactant micellar-hybridized supramolecular gels. Electrochimica Acta 2013;90:326-331
  268. 268. Fu C, He D, Yu Y, Wu S, Dong C, Wang H. Fluorescent sensitization of gemini surfactant micellar-hybridized supramolecular hydrogels. Journal of Luminescence 2017;181:8-13
  269. 269. Sakthivel S, Gardas RL, Sangwai JS. Effect of alkyl ammonium ionic liquids on the interfacial tension of the crude oil–water system and their use for the enhanced oil recovery using ionic liquid-polymer flooding. Energy & Fuels. 2016 Mar 17;30(3):2514-2623
  270. 270. Pal N, Babu K, Mandal A. Surface tension, dynamic light scattering and rheological studies of a new polymeric surfactant for application in enhanced oil recovery. Journal of Petroleum Science & Engineering. 2016 Oct;146:591-600
  271. 271. Malkin AY, Khadzhiev SN. On the rheology of oil (review). Petroleum Chemistry. 2016 Jul;56(7):541-551
  272. 272. Zhou M, Zhao J, Hu X. Synthesis of bis[N,N′-(alkylamideethyl)ethyl] triethylenediamine bromide surfactants and their oilfield application investigation. Journal of Surfactants and Detergents. 2012 May;15(3):309-315
  273. 273. Bi ZC, Qi LY, Liao WS. Dynamic surface properties, wettability and mimic oil recovery of ethanediyl-α, β-bis (cetyldimethylammonium bromide) on dodecane modified silica powder. Journal of Materials Science. 2005;40(11):2783-2788
  274. 274. Nguele R, Sasaki K, Salim HS-A, Sugai Y. Physicochemical and microemulsion properties of dimeric quaternary ammonium salts with trimethylene spacer for enhanced oil recovery. Colloid & Polymer Science. 2015 Dec;293(12):3487-3497
  275. 275. Qiu LG, Cheng MJ, Xie AJ, Shen YH. Study on the viscosity of cationic gemini surfactant–nonionic polymer complex in water. Journal of Colloid and Interface Science. 2004 Oct;278(1):40-43

Written By

Bogumil E. Brycki, Iwona H. Kowalczyk, Adrianna Szulc, Olga Kaczerewska and Marta Pakiet

Submitted: 05 October 2016 Reviewed: 23 March 2017 Published: 05 July 2017