Liquid crystals composed of N-acylamino acids. I. Circular dichroism and selective light transmission in cholesteric liquid crystals composed of N-acylamino acids and organic solvents

Abstract

Optically active '-acylamino acids formed a new type of lyotropic cholesteric liquid crystals when they were swelled and dispersed as a suspension in solvents such as benzene, chlorobenzene, chloroform, and «-hexane. An appropriate solvating ability to swell but not to dissolve any given '-acylamino acid may be a necessary condition for a solvent to form the liquid crystalline phase which appears as a suspension. These suspended liquid crystals showed some characteristics of lyotropic cholesteric liquid crystals: (1) circular dichroism (CD) bands with a single sign, (2) the liquid-crystal-induced CD (LCICD) bands due to achiral molecules added to these systems, and (3) a spherulite-like phase having an optically negative sign. These suspended liquid crystals showed the iridescent color typical of cholesteric liquid crystals. These colors were found to originate from the difference of the refractive indices of the solvents from those of suspended liquid crystals, the so-called "Christiansen effect", and not from the chiral structure in the liquid crystals.We reported recently that the amorphous powdered Nlauroyl-L-glutamic acid (l-LGA),2 which was soaked into aromatic solvents such as benzene or toluene, showed not only birefringence under a polarized microscope but also a positive

Phase Behavior and Effect of Enantiomerism on Potassium N -Dodecanoyl Alaninate/Water/Decanol Systems

“…However, we are not aware of any report for the existence of such phase between the V 1 and the L a phase in a ternary phase diagram. The cosurfactant-induced [V 1 L a H 2 O m ] phase transformation observed here is the typical pattern observed in ionic surfactant/alcohol/water systems (49).…”

“…Probably, the optical activity in these biopolymers play important role in the biology and chemistry of these assemblies. Therefore, study of the role of optical activity in the self-aggregation of simple and optically-active surfactants, like N-acylaminoacids, would be an important step in understanding more complicated systems which show both micellization and enantiomerism (2,3).…”

Birefringent physical gels of N-(4-n-alkyloxybenzoyl)-l-alanine amphiphiles in organic solvents: The role of hydrogen-bonding

“…A variety of liquid-crystalline materials have been prepared by self-assembly through H-bond formation [53,54]. It has been observed that gelators containing optically active acids and steroidal and condensed aromatic rings form lyotropic liquid crystal [55,56].…”

Effect of lecithin on organogel formation of 12‐hydroxystearic acid

“…The results undoubtedly suggest that the triglyceride moiety interacts with the carboxyl group in 12-HSA or stearic acid. Capitani et al (9) studied organogel formation in a lecithin/cyclohexane system by NMR. Steep increases in the viscosity of the system were observed on the addition of small amounts of water.…”

“…A large number of low-molecular weight organic substances, such as organometallic complexes (1,2), 12-hydroxystearic acid (12-HSA) (3)(4)(5)(6)(7), dibenzylidene sorbitol (8), various alkylamide derivatives (9)(10)(11), androstanyl derivatives (12,13), anthracenyl derivatives (14,15) and cholesterolbased derivatives (15,16), are known to form organogels with network structures in various organic liquids. These substances are widely utilized as regulators of viscoelastic properties for greases and cosmetics, as solidifier for used cooking oil, and as reagents for the recovery of ocean-spilled oil.…”