Liquid crystalline polyacrylates containing biphenyl and chiral terminal groups in the side chain, 2. Influence of the nature of the chiral group

Abstract

AbstractAcrylate monomers with a chiral group have been synthesized bearing a propyl, isopropyl or benzyl substituent on the asymmetric carbon. All of the monomers are crystalline. Above their melting point, they give a clear, isotropic melt. The corresponding polymers have been prepared by free radical polymerization. They were examined by differential scanning calorimetry, optical microscopy and X‐ray diffraction. They were found to show a reproducible liquid‐crystal behavior. On cooling from the isotropic state, SA, S (or S) and crystal‐like (probably SH or SH′) phases become evident. Our results do not preclude the existence of a S phase between the SA and S phases. It is noteworthy that polyacrylates of the same series but with side chains terminated by a chiral group bearing a methyl substituent exhibit SA, SB and crystal‐like (probably SE) phases.