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Synthesis and characterization of a series of smectic liquid crystalline elastomers
Author(s) -
He XiaoZhi,
Zhang BaoYan,
Xiao LingJiu,
Wang Yang,
Wu HaiQuan
Publication year - 2005
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.21767
Subject(s) - mesophase , materials science , mesogen , differential scanning calorimetry , elastomer , liquid crystal , polymer , monomer , glass transition , polymer chemistry , fourier transform infrared spectroscopy , polymerization , phase (matter) , phase transition , crystallography , chemical engineering , composite material , organic chemistry , chemistry , liquid crystalline , thermodynamics , physics , optoelectronics , engineering
Abstract A series of new smectic and cholesteric liquid crystalline elastomers was prepared by graft polymerization of mesogenic monomer with the chiral and nonmesogenic crosslinking agent using polymethylhydrosiloxane as backbone. The chemical structures of the monomers and polymers obtained were confirmed by Fourier transform infrared (FTIR), proton nuclear magnetic resonance spectra ( 1 H‐NMR). The mesomorphic properties were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X‐ray diffraction measurements (XRD). M 1 showed smectic (S B , S C , S A ) and nematic phases during the heating and the cooling cycles. Polymer P 0 and elastomer P 1 exhibited smectic B phase, elastomers P 2 –P 5 showed smectic A phase, P 6 and P 7 showed cholesteric phase, and P 8 displayed stress‐induced birefringence. The elastomers containing less than 15 mol % M 2 displayed elasticity and reversible phase transition with wide mesophase temperature ranges. Experimental results demonstrated that the glass transition temperatures decreased first and then increased; melting temperatures and the isotropization temperatures and the mesophase temperature ranges decreased with increasing content of crosslinking unit. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 498–506, 2005