THE EFFECTS OF COMPACTION AND SUBSTRATE ON THE SUPRAMOLECULAR STRUCTURE OF SOLIDIFYING MELTS

Crystallization of cholesteryl pelargonate and 4-octyloxy-4'-cyanobiph enyl (mesogeneous compounds) and of cholesterol and terphenyl (structu rally similar but nonmesogeneous compounds) was studied by differentia l scanning calorimetry. For cholesterol derivatives subjected to a pre liminary compaction in the solid or liquid state or solidified in a th in layer sandwiched between two substrates, anomalously low undercooli ng values were obtained in several melting and crystallization cycles. It was suggested that the mechanism of this phenomenon consists of a change in the supramolecular structure. This idea was supported by the results of the X-ray diffraction analysis.