Liquid Crystalline Polymers Containing Heterocycloalkane Mesogens. 1. Side-Chain Liquid Crystalline Polymethacrylates and Polycrylates Containing 2,5-Disubstituted-1,3-Dioxane Mesogens

摘要

Polymethacrylates and polyacrylates containing 2-(p-hydroxphenyl)-5-(p-methoxyphenyl)-1-, 3-dioxane as a mesogenic unit and an aliphatic spacer containing eleven methylene units were synthesized. Their phase behavior was studied by differential scanning calorimetry and optical polarization microscopy, and compared with the phase behavior of the corresponding polymethacrylates and polyacrylates based on 4-methoxy-4'-hydroxbiphenyl mesogen. All polymers present smectic mesomorphism. The 2,5-disubstituted-1,3-dioxane mesogen resembles a terphenyl mesogen in which the internal phenyl ring was hydrogenated. Even so, when compared with the biphenyl containing polymers, the glass transition temperatures of the 1,3-dioxane containing polymers are lower, although their isotropization occurs at higher temperatures. Keywords: Side-chain thermotropic liquid crystalline polymers.