Synthesis and Characterization of Bifunctional Liquid-Crystalline Monomers Showing Smectic C Phase. Photopolymerization and Cross-Linking

Abstract

Novel syntheses of bifunctional liquid-crystalline acrylate and methacrylate monomers are described. Thermal and microstructural characterization of the monomers using small-angle X-ray scattering, differential scanning calorimetry, and optical microscopy revealed the presence of smectic A, smectic C, and smectic E phases. Photopolymerization of the bifunctional monomers conducted at different temperatures preserved the monomeric liquid-crystalline structure in the cross-linked polymers. The densely cross-linked polymers showed thermal reversibility. Mixtures of these monomers and chiral monofunctional liquid-crystalline monomers exhibited chiral smectic C mesomorphism that was permanented by photopolymerization and subsequent cross-linking.