Suppression of side chain crystallization and transformation of monotropic mesophases into enantiotropic mesophases by copolymerization of the parent polymers' monomer pairs containing constitutional isomeric mesogenic side groups

Abstract

The synthesis and characterization of several copolymers based on the monomer pairs of 11-[4-methoxy-(4′-oxy)-α-methylstilbene]undecanyl methacrylate (4-11-MA) and 11-[4-oxy-4′-methoxy)-α-methylstilbene]undecanyl methacrylate (4′-11-MA), 11-[4-methoxy-(4′-oxy)-α-methylstilbene]undecanyl acrylate (4-11-AC) and 11-[4-oxy-(4′-methoxy)-α-methylstilbene]undecanyl acrylate (4′-11-AC), and 8-[4-methoxy-(4′-oxy)-α-methylstilbene]octyl acrylate (4-8-AC) and 8-[4-oxy-(4′-methoxy)-α-methylstilbene] octyl acrylate (4′-8-AC) are described In the case of polymers with polymethacrylate backbones, the copolymerization of the two constitutional isomeric mesogenic monomers cancels the side chain crystallization tendency characteristic of their parent homopolymers. Subsequently, the copolymer presents a broader mesophase temperature range than any of the two parent homopolymers. In the case of polymers with polyacrylate backbones, copolymerization suppresses the tendency towards side chain crystallization and subsequently, transforms one or even two monotropic mesophases into enantiotropic mesophases.