Lyotropic liquid crystal phase formation in l-(alkanoylmethyl amino) 1-deoxy-D-glucitols

Abstract

The lyotropic and thermotropic liquid crystals of a series of 1-(alkanoylmethyl amino) 1-deoxy-D-glucitols (C₈–C₁₂, C₁₈₌) oleoyl derivative) have been investigated by polarizing optical microscopy and differential scanning calorimetry. For chain lengths longer than the octanoyl derivative, the pure compounds form a lamellar (smectic A) phase before melting to the isotropic liquid. Both the liquid crystal and isotropic phases of the neat surfactant and aqueous mixtures supercool to form metastable states. In water the octanoyl derivative forms hexagonal (H₁) phase, while the C₈–C₁₂ compounds give H₁, cubic (V₁) and L_α mesophases. Only the L_α phase is observed with the oleoyl derivative.