Side group functionalized liquid crystalline polymers and blends VIII. Nematic and SmAre phase formation in hydrogen-bonded blends of smectic side group LC polymers and a low molar mass dopant |
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| Authors: | E. B. Barmatov A. P. Filippov V. P. Shibaev |
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| Affiliation: | 1. Department of Chemistry , Facility of Science, Cairo University , Cairo, Egypt magdinaoum@yahoo.co.uk;3. Department of Chemistry , Facility of Science, Cairo University , Cairo, Egypt |
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| Abstract: | ![]()
Hydrogen-bonded blends based on smectic side group functionalized LC copolymers containing 4-alkyloxybenzoic acid fragments (proton donor) and a non-mesogenic low molecular mass dopant 4-cyanophenyl pyridine-4-carboxylate or 4-methoxyphenyl-d4 pyridine-4-carboxylate (proton acceptor) were obtained. The blends containing 10-35 mol % of low molecular weight dopant form nematic (I-N-SmA) or re-entrant SmA phases (I-SmA-N-SmAre). The temperature dependence of the order parameter S, the birefringence Δn, and the splay K 1 and bend K 3 elastic constants of the nematic phase were studied by 2H NMR spectroscopy and the Fréedericksz method of threshold transitions in a magnetic field. A mechanism for the destruction of the SmA phase and the formation of the nematic phase in the hydrogen-bonded blends is suggested. |
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| Keywords: | lateral substitution binary mixtures 4-(3′-fluoro phenylazo)-2-(or 3-) substituted phenyl-4′-alkoxyben-zoates |
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