Bazı kiral ve akiral kısmen florlu sürfaktantların izotrop miselli çözelti ve liyotropik sıvı kristal özelliklerinin hidrojenli eşdeğerleri ile karşılaştırılması

In this study, we mainly examined lyotropic intrinsic cholesteric phase properties of some amino acid based chiral surfactants with partly fluorinated and hydrogenated chains to investigate the effect of the twist structure of fluorocarbon chain on the helical twisting power of chiral surfactants. For this purpose, we synthesized some chiral and achiral surfactants and determined fluorinated/hydrogenated counterpart surfactants, taking into account 1 CF2=1.5 CH2 rule in terms of hydrophobicity, from their critical micelle concentrations via electrical conductivity measurements. Then, we prepared lyotropic mixtures exbiting discotic cholesteric phases by dissolution of chiral surfactants Lalaninehydrochloride undecylester (L-AUnDE), L-serinehydrochloride undecylester (L-SUnDE) and their partlyfluorinated counterparts (L-APFOE and L-SPFOE, respectively) into sodium chloride (NaCl)/water mixtures, separately.The pitch measurements were performed by laser diffraction method to evaluate the helical twisting powers of each fluorinated/hydrogenated chiral surfactants. The results indicated that the twist structure of fluorocarbon chain provides higher helical twisting power with respect to the hydrocarbon chain, which supports the intramicellar chirality model proposed in the literature.