Effect of the degree of protonation of amino acid dopants in Chirality amplification in DSCG Lyotropic Nematic phases.

Abstract

Disodium Cromoglycate (DSCG), a lyotropic liquid crystal in water, is shown to be an amplifier of chirality when doped with small chiral molecules. Here, we study the behaviour of the DSCG nematic phase in the presence of three aminoacids with different degrees of protonation: L-Alanine, L-Arginine·HCl and L-Arginine. The results demonstrate that the sign of the helicity of the doped nematic phase (i.e., a cholesteric phase) depends on the sign of the Helical Twisting Power of the dopant.