Effect of a Branched Spacer on the Structure and Properties of a Chiral Mesogenic Acrylate and Corresponding Polyacrylate

Mesogenic acrylate with a chiral centre incorporated into the flexible spacer unit and corresponding polymers prepared by both in-situ photopolymerization and radical solution polymerization have been investigated by polarizing optical microscopy, differential scanning calorimetry, X-ray diffraction and IR spectroscopy. Monolayered structure of the S-I* phase formed by the monomer was found to be periodically broken by defects caused by the branched spacers. Surface-induced orientation behaviour of the monomer in the S-I* phase was analyzed over wide temperature range. In the absence of a photoinitiator, UV irradiation of the monomer led to fast and efficient polymerization. The macroscopic orientation and the structure of the S-I* phase on a microscopic scale were shown to retain during the reaction. The polymers prepared by solution polymerization exhibit S-F* and S-C* phases with bilayer structure. The systems under study are devoid of ferroelectric properties and this behaviour is discussed in terms of the effect of the chiral branched spacer on molecular packing.