Mesomorphic Behaviour of the Cholesteryl Esters-I: p-n-Alkoxybenzoates of Cholesterol
A homologous series of Cholesteryl p-n-alkoxybenzoates has been synthesised and its mesomorphic behaviour studied. All the members of the series are enantiotropic mesomorphic. The higher members starting with cholesteryl p-n-heptyloxybenzoate exhibit enantiotropic polymesomorphism-smectic and cholesteric mesophases; the smectic mesophase increases with the increase in the alkyl chain length in the series at the cost of the cholesteric mesonhase.
All the members of the series exhibit iridescent colours with the change in temperature, the colour intensity decreasing as the alkyl chain length increases and the last two members of the series do not show any colour change. At the smectic-cholesteric phase transition, a colour spectrum is observed both while heating as well as cooling. The higher members in the series show homoeotropic smectic texture on cooling.
KeywordsFatty Acid Ester Alkyl Chain Length Thionyl Chloride Smectic Phase Aromatic Ester
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