The Mesomorphic Behavior of Cholesteryl n-Alkyl Carbonates

Abstract

A homologous series of cholesteryl n-alkyl carbonates has been prepared and their mesophases investigated. Different groups can be distinguished depending on the length of the alkyl chain. The first two members exhibit a monotropic high-temperature color band, the next two members an enantiotropic high-temperature color band, followed by a monotropic low-temperature color band without an interruption in the color sequence the following five members an enantiotropic high-temperature and a clearly separated low-temperature color band, and the last four members a monotropic high-temperature and a separated monotropic low-temperature color band. The mechanical sensitive enantiotropic high-temperature color band could only be observed in reflection under the microscope. The monotropic low-temperature color band, which is essentially induced by disturbance, was found in both reflection and transmission, with the colors of the same intensity.