The Preparation and Measurement of the Temperatures and Heats of Transition of the Liquid Crystal Phases of Two Homologous Series: 2-hydroxy-1,2-bis(4-n-alkyloxyphenyl)-1-(4-ethoxyphenyl)iminoethane and (4-n-decyloxyphenyl)iminoethane

Abstract

Two homologous series A and B, viz, 2-hydroxy-1,2-bis(4-n-alkyloxyphenyl)-1-(4-ethoxyphenyl) and 2-hydroxy-1,2-bis(4-n-alkyloxyphenyl)-1-(4-n-decyloxyphenyl)iminoethanes have been prepared with varying number of carbon atoms in the alkoxy chain.

The transition temperatures and textures of the mesophases were determined with a polarizing microscope equipped with a Mettler FP-5 hot stage. The transition temperatures and transition heats were measured using a Perkin-Elmer DSC-2.

The compounds of the two series with the same number of carbon atoms do not exhibit the same mesophases. Series A exhibits a nematic phase for compounds with n = 1–16 and also a smectic phase for compounds with n = 10, 12 and 16. Series B shows a nematic mesophase for compounds with n ≤ 8 and either one or two smectic mesophases for compounds with n ≥ 5.