Nanoemulsions, kinetically stable and thermodynamically unstable colloidal liquid-in-liquid dispersions with droplet sizes in the order of 20–500 nm mainly consist of oil, surfactants, co surfactants and an aqueous phase. There are various methods for the fabrication of Nano-emulsions which can be divided based on the energy required—High energy emulsification methods and Low energy emulsification methods. High energy emulsification includes methods like Ultra sonication, high pressure homogenization using either microfluidizers or high-pressure homogenizers. Low energy emulsification has drawn attention since they are soft, nondestructive and cause no damage to encapsulated molecules and includes methods like phase inversion temperature, solvent displacement, phase inversion composition method. Nanoemulsions are best suited for drug delivery systems because of their lipophilic nature, optical clarity and surface area. Owing to their nature to prevent flocculation and inherent creaming, nanoemulsions find an important place in the cosmetic industry also. This chapter provides an insight into the use of nanogels, emulsion based wet wipes and PEG free nanoemulsions in cosmetics. In the food industry, nanoemulsions are utilized for the production of functional foods. Some of the patented nanoemulsions and their commercial applications have also been mentioned.
Part of the book: Nanoemulsions
Sonochemistry is a branch dealing with effects of chemical as well as sound wave as the name suggest. The sound waves are ultrasonic, i.e., high frequency waves (20 kHz can extent to 10 MHz and above) beyond the range of a human ear (20–20 kHz). Sonochemistry technology is incorporated into both mechanistic and synthetic studies. An important event called acoustic cavitation take place where microbubbles grow and under the influence of ultrasonic waves they collapse. Sonoluminescence is one of the outcomes of cavitation which leads to homogeneous sonochemistry. Sonochemistry has also entered one of the major developing field biotechnology from basic activation of enzyme to preparation of catalyst. It is also used for the fabrication of nanomaterial which comes under the liquid phase method. One disadvantage of nanomaterial preparation is the amount of time it consumes to show results. This can be eliminated when biotechnological research is conducted in conjunction with sonochemical application. Latest research results have proved that ultrasound irradiation is both time and cost-effective approach for any bio-processes like enhancement of emulsification and trans-esterification of fatty acids for bio-fuel products. Bio-process monitoring and dewatering of sludge have also been accelerated. This chapter contains introductory information on sonochemistry.
Part of the book: Sonochemical Reactions