3. Shear Induced Molecular Alignments of A Side-Chain Liquid Crystalline Polyacetylene Containing Biphenyl Mesogens
作者：J. Geng, X. Zhao, E. Zhou, G. Li,* J. W. Y. Lam, B. Z. Tang
關鍵字：Liquid-crystalline polymer, Polyacetylenes, Shear orientation
論文來源：期刊
具體來源：Polymer 2003, 44, 8095-8102
發表時間：2003年
Mesomorphic properties of a side chain liquid crystalline polyacetylene, poly(11-{[(40-heptyloxy-4-biphenylyl)carbonyl]oxy}-1-undecyne) (PA9EO7), are investigated using polarized optical microscope, X-ray diffraction, and transmission electron microscope. Polymer PA9EO7 forms enantiotropic smectic A and smectic B phases. It also exhibits an additional high order smectic phase, a sandwich structure consisting of different molecular packing of biphenyl mesogenic moieties from that of alkyl spacers and terminals, when it is prepared from its toluene solution. Shearing the polymer film at its smectic A phase generates banded texture with the alignment of the backbones parallel to the direction of shear force. While at its high order smectic phase, the mesogen pendants of the polymer are arranged parallel to the direction of shear. The different mesomorphic behaviors arise from different molecular alignments influenced by the fluidity.