Some novel disaccharide-derived liquid crystals

Abstract

Some novel disaccharide-derived amphiphiles, in which the hydrophobic long chain alkyl group and an alpha -D-glucose moiety are separated by a hydrophilic five carbon spacer or a hydrophobic furan residue, were investigated as to their mesomorphic properties using DSC, thermomicroscopy and various X-ray methods. All compounds exhibit a smectic A phase, characterized by aggregation to a bilayered S structure. The layer thickness d, measured by A X-ray, correlates with the presence of polar d and non-polar moieties, adjoining molecules interacting via hydrogen bonding. Based on the known structural concepts for sugar-derived liquid crystals, a model is suggested to account for the observed S mesomorphic behaviour of two N -alkanoyl derivatives of (glucosylox dymethylfuryl) methylamine, i.e. species in which sugar and long chain fatty acid are separated by a quasi-aromatic furan residue, is unusual, as different X-ray methods invariably give the same odd indicative of a smectic layer thickness of three to four molecules. layer arrangement. The A d -value indicative of a smetic layer thickness of three to four molecules.