Anomalous smectic mesomorphism of 4,4'-di-n-pentyloxyazoxybenzene

Abstract

Calorimetric and optical texture studies reveal the existence of a previously unrecognised, stable, highly ordered and enantiotropic smectic phase of C5 (4,4'-din-ent yloxasoxybensene). This represents a distinctly anomalous behaviour as the next five homologs, C6 - C10, do not exhibit such a highly ordered smectic phase. It is shown that configurationdl melting of the alkyl end-chains can largely account for the observed thermodynamic parameters of the solid-smectic transition of C5.