Side-chain copolymers containing smectic monomer and chiral reagent-synthesis and characterization

摘要

A series of new chiral side-chain liquid-crystalline polymers were prepared containing smecticnematic monomer and nonmesogenic chiral monomer. All polymers were synthesized by graft polymerization using polymethylhydrosiloxane as backbone. The mesomorphic properties were investigated by differential scanning calorimetry, polarizing optical microscopy, thermogravimetric analyses, and X-ray diffraction measurements. The chemical structures of the monomers and polymers obtained were confirmed by Fourier transform infrared, proton nuclear magnetic resonance spectra (H-1 NMR). M, showed smectic (S-B, S-C) and nematic phase on the heating and the cooling cycle. Polymers P-0-P-2 were in chiral smectic A phase, while P-3-P-5 were in cholesteric phase, P-6 has bad LC properties, and P-7 has no LC properties. Experimental results demonstrated that nonmesogenic chiral moiety and LC mesogenic with long carbochain offered the possibility of application because of its lower glass transition temperature, and the glass transition temperatures and isotropization temperatures and the ranges of the mesophase temperature reduced with increasing the contents of chiral agent. (C) 2008 Wiley Periodicals, Inc.