Synthesis of high temperature cholesteric copolysiloxanes and their use as stationary phases for high resolution gas chromatography

Abstract

The synthesis of side-chain liquid crystalline copolysiloxanes containing-cholesteryl4-(10-undecen-1-yloxy)biphenyl-4'-carboxylate and 4-biphenyl 4-allyloxybenzoate mesogenic side groups is present. Differential scanning calorimetry, optical polarizing microscopy measurements reveal wide temperature range of cholesteric phase for all copolysiloxanes. The cholesteric temperature range depends upon the monomer feeding ratio. The copolysiloxanes containing higher percentage of cholesteryl 4-(10-undecen-1-yloxy)biphenyl-4'-carboxylate side group reveal wider temperature range of cholesteric phase. The synthesized copolysiloxanes were used as stationary phase in gas chromatography capillary columns. They show very unique chiral resolution properties for various kinds of enantiomers, i.e., linalool, menthol and menthone.