Synthesis and Photoresponsive Behaviors of Well-Defined Azobenzene-Containing Polymers via RAFT Polymerization

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• 作者：Yuanyuan Zhang ; Zhenping Cheng ; Xinrong Chen ; Wei Zhang ; Jianhong Wu ; Jian Zhu ; Xiulin Zhu
• 刊名：Macromolecules
• 出版年：2007
• 出版时间：July 10, 2007
• 年：2007
• 卷：40
• 期：14
• 页码：4809 - 4817
• 全文大小：261K
• 年卷期：v.40,no.14(July 10, 2007)
• ISSN：1520-5835

文摘

The well-defined photoresponsive polymethacrylate containing azo chromophore, poly{1'-octyloxy-4'-(6-methacryloxy)hexyloxy-5'-phenylmethaneone-(2-phenyl)azobenzene (AHMA)} (PAHMA), was preparedvia reversible addition-fragmentation chain transfer (RAFT) polymerization in anisole solution using 2-cyanoprop-2-yl 1-dithionaphthalate (CPDN) as the RAFT agent and 2,2'-azobis(isobutyronitrile) (AIBN) as an initiator. Thekinetic plots of polymerization were first-order and the molecular weights (M_n(GPC)s) of the homopolymer (PAHMA)with relatively low polydispersity index values (PDIs 1.37) increased with monomer conversions throughoutthe polymerization processes. Furthermore, the kinetic plots of chain extension with both methyl methacrylate(MMA) and styrene (St) using the obtained PAHMA as a macro-RAFT agent were also first-order. The M_n(GPC)sof the diblock copolymers, PAHMA-b-PMMA and PAHMA-b-PS, increased with the respective monomerconversions. These results indicated that most of the PAHMA chains were still "living". The structure and propertiesof the polymers were characterized by ¹H NMR, GPC, and UV-vis spectra. The photoisomerization of the polymerwas examined. On irradiation with a linearly polarized Kr⁺ laser beam, the birefringence was induced in thepolymer films to the level of 0.075. With illumination of linearly polarized Kr⁺ laser beam at modest intensities(120 mW/cm²), significant surface relief gratings (SRGs) formed on the polymer films were observed.