Thermotropic Liquid Crystals Based on Oligosaccharides. n-Alkyl 1-O-β-D-Cellobiosides

Article abstract of DOI:10.1246/bcsj.67.346

n-Alkyl 1-O-β-D-cellobiosides with an alkyl length ranging from 7 to 18 in carbon number m were synthesized, and their thermal properties were studied in comparison with those of the already-known monosaccharide homologues, n-alkyl 1-O-β-D-glucopyranosides.The cellobiosides were found to exhibit a thermotropic mesophase at higher temperatures than the glucopyranosides.Depending on m and thermal history, the cellobiosides showed various textures such as homeotropic, transient batonnets, polygonal, and fan-shaped textures.Like in the case of the monosaccharide homologues, the difficulty of aligning the samples prohibited a full classification of the mesophase, but the X-ray diffractograms of the unaligned cellobiosides indicated that their mesophase belongs to smectic A (or less possibly, smectic C).The m dependence of the lamella thickness was much weaker than (about half) that of the monosaccharide homologues.Possible molecular arrangements of the cellobiosides in the mesophase were presented.