Mesomorphic Behavior of Compounds of Low Thermal Phase Stability

Publisher Website
Google Scholar
Abstract
A number of new Schiff's bases showing nematic mesomrophism of low thermal stability (to below O°C) were found to also deviate somewhat from known compounds in the relation of transition temperatures to substituent chain variations in their homologous series. Besides a tendency towards rising nematic-isotropic transitions in ascending series, a regular alternation in the solid-nematic and smectic-nematic transitions from even to odd numbered members of the series was observed. This only recently reported alternation was in phase with the corresponding fluctuations in the nematic-isotropic transitions. It was also found that a replacement of methylene groups by oxygen in alkoxy-substituted schiff's bases resulted in a thermal destabilization of all phases and a reduction in the incidence of mesomorphism. The effects of structural changes in these simple mesomorphic compounds on thermal phase stabilities showed many analogies to n-alkanes and aliphatic ethers implying that the forces which determine the structure of these mesomorphic phases are not very different from those which govern simple crystalline lattices.

This publication has 13 references indexed in Scilit: