Parvathalu Kalakonda

By Parvathalu Kalakonda and Germano S Iannacchione

The complex specific heat is reported over a wide temperature range for a negative dielectric anisotropy alkoxyphenylbenzoate liquid crystal (9OO4) and carbon nanotube (CNT) composites as a function of carbon nanotube concentration. It has been observed that the combination of nanotubes (CNT) and liquid crystal (LC) provides a very useful way to align CNTs and also dramatically increases the order in the liquid crystal performance, which is useful in liquid display technology (LCD). The calorimetric scans were performed between 25 and 95°C temperatures, first allowed cooling and then heating for CNT concentration ranging from ϕw = 0 to 0.2 wt%. All 9OO4/CNT composite mesophases have transition temperatures about 1 K higher and a crystallization temperature 4 K higher as compared to the pure 9OO4 liquid crystal. A strongly first-order specific heat feature is observed, which is 0.5 K higher than in the pure 9OO4. The transition enthalpy for the composite mesophases is observed 10% lower than the pure liquid crystal. We interpret that these results arising from the LC-CNT surface interaction lead to pinning orientational order uniformly along the CNT, without pinning the position of the 9OO4 molecule. These effects of incorporating CNTs with LC are likely due to elastic coupling between CNT and LC. These effects of incorporating CNTs into LCs are likely due to an "anisotropic orientational" coupling between CNT and LC, the change in the elastic properties of composites and thermal anisotropic properties of the CNTs.

Part of the book: Carbon Nanotubes

By Parvathalu Kalakonda and Sreenivas Banne

The interaction between the silver nanoparticle and peptide surfaces has been of increased interest for the applications of bionanotechnology and tissue engineering. In order to completely understand such interactions, we have examined the optical properties of peptide-coated silver nanoparticles. However, the effect of peptide binding motif upon the silver nanoparticles surface characteristics and physicochemical properties of these nanoparticles remains incompletely understood. Here, we have fabricated sodium citrate stabilized silver nanoparticles and coated with peptide IVD (ID3). The optical properties of these peptide-capped nanomaterials were characterized by UV-visible, transmission electron microscopy (TEM), and z-potential measurement. The results indicate that the interface of silver nanoparticles (AgNP)-peptide is generated using ID3 peptide and suggested that the reactivity of peptide is governed by the conformation of the bound peptide on the silver nanoparticle surface. The interactions of peptide-nanoparticle would potentially be used to fabricate specific functionality into the various peptide-capped nanomaterials and antibacterial applications.

Part of the book: Silver Nanoparticles