Synthesis and phase behaviour of a poly{2,5-bis[(p-ethoxyphenoxy) carbonyl] benzyl acrylate}-based mesogen-jacketed liquid crystalline copolymer

Mesogen-jacketed liquid crystal polymers have attracted considerable interest in recent years. In this paper, a series of poly (PEPCS)-based mesogen-jacketed liquid crystal copolymers (MJLCPs) with a different 4-hydroxybutyl acrylate (HEA) content has been synthesised and characterised using Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and polarising optical microscopy (POM). The hydroxyl groups are attached to the backbone in the PEPCS-co-HEA copolymers to facilitate further chemical crosslinking. These PEPCS-based MJLCPs show a reversible phase transition when the HEA content is lower than 30 wt%. T_g and T_i shift to lower temperatures as the HEA content increases. POMstudies reveal that the PEPCS and PEPCS-co-HEA copolymers all show a transition from the nematic to isotropic phase on heating and from the isotropic to nematic phase on cooling. Below T_g, the long range orientational ordering of the mesogenic units is fixed.