Arabinomannan Glycolipids Reveal Oligosaccharide Dependent Transition From Smectic to Hexagonal Columnar Mesophase Structures

Abstract A series of arabinomannan mono, di, tri, and tetra‐saccharide glycolipids constituted with a uniform lyophilic segment is investigated. The oligosaccharide and the lyophilic alkylene moieties in these glycolipids promote an amphiphilicity‐driven mesomorphism. The thermotropic nature of these glycolipids and the mesophase structures vary depending on the saccharide constitution. Whereas mono, di and trisaccharide glycolipids prefer lamellar mesophase structures, the tetrasaccharide possesses a columnar structure. The mesophase structures are evaluated by variable temperature X‐ray diffraction measurements and correlated further by energy‐minimized molecular structure calculations. Fractional volumes of the carbohydrate portion in the series gradually vary and with that the molecular packing in the mesophase. As the ratio of fractional volume of carbohydrate‐to‐lipid increase, the character of the mesophase changes from lamellar to columnar. The work illustrates that nonionic glycolipids fully retain amphiphilicities and the mesophase properties across the glycolipids, even when there are significant changes on the oligosaccharide constitution and none in the lyophilic segment of the glycolipids.