Liquid Crystalline Phase Transition in Organophosphazenes with 4-Octyloxybiphenyl Mesogenic Groups
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Cyclotriphosphazenes with the same 4-octyloxybiphenyl mesogenic side groups have been synthesized and were studied their phase transition and liquid crystallinity using DSC measurements and polarizing microscope observations. We found an enantiotropic smectic C phase in hexakis(4-(4′-octyloxy)biphenoxy)cyclotriphosphazene but no liquid crystalline phase was observed in octakis(4-(4′-octyloxy)biphenoxy)cyclotetraphosphazene. These may originate from each of the three side chains of the cyclotriphosphazene molecules pointed upwards and downwards perpendicularly from the cyclotriphosphazene ring, which helps the formation of the liquid crystalline layer structure. However, in the cyclotetraphosphazene, the eight side chains orient relatively at random and this prevents the formation of the mesogenic layer structure.
- Chemistry Letters
Chemistry Letters 1997(10), 1001-1002, 1997-10
The Chemical Society of Japan