Synthesis of novel three‐arm star azo side‐chain liquid crystalline polymer via ATRP and photoinduced surface relief gratings |
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Authors: | Yuanyuan Zhang Wei Zhang Xinrong Chen Zhenping Cheng Jianhong Wu Jian Zhu Xiulin Zhu |
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Institution: | 1. Key Laboratory of Organic Synthesis of Jiangsu Province, School of Chemistry and Chemical Engineering of Soochow (Suzhou) University, Suzhou 215006, China;2. Lianyungang Higher Vocational Technology College of Traditional Chinese Medicine, Lianyungang 222006, China;3. Institute of Information Optical Engineering, Suzhou University, Suzhou 215006, China |
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Abstract: | A three‐arm star azo side‐chain liquid crystalline (LC) homopolymer, poly6‐(4‐methoxy‐4‐oxy‐azobenzene) hexyl methacrylate] (PMMAZO), was synthesized by atom transfer radical polymerization (ATRP) method. The polymerization of 6‐(4‐methoxy‐4‐oxy‐azobenzene) hexyl methacrylate proceeded in a controlled/“living” way. A series of three‐arm star LC block copolymers (PMMAZO‐b‐PMMA) were also synthesized. The polymers were characterized by 1H NMR, gel permeation chromatograph, and UV–vis spectra, respectively. The both polymers of PMMAZO and copolymers of PMMAZO‐b‐PMMA exhibited a smetic phase and a nematic phase. As concern to the PMMAZO, the glass‐transition temperature (Tg) and phase‐transition temperature from the smetic to nematic phase and from the nematic to isotropic phase increased with the increase of molecular weight (Mn(GPC)) of PMMAZO. The phase transition temperature of the block copolymers, PMMAZO‐b‐PMMA, with the same PMMA block was similar to that of PMMAZO. However, the Tg of the PMMAZO‐b‐PMMA decreased at low azo content and then increased with the increasing Mn(GPC) when azo content was above 61.3%. With illumination of linearly polarized Kr+ laser beam at modest intensities (35 mW/cm2), significant surface relief gratings formed on PMMAZO films with different molecular weights were observed. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 777–789, 2008 |
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Keywords: | ATRP azo polymer liquid crystalline 6‐(4‐methoxy‐4‐oxy‐azobenzene) hexyl methacrylate surface relief gratings three‐ arm star polymer |
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