Synthesis And Characterization Of Organic-Inorganic Polymer Containing Azobenzene

Azobene compounds have been confined to be used as simple stains for a long time. Since the trans-cis photoisomerization property which occus under the light irradiation has been reported, azobenzene compounds have been attracted considerable attention in meterials science. The azobenzene-based functional materials have become a hot research. The trans-cis photoisomorization of azobenzene causes large changes in molecular geometry and dipole moment. The photoisomerization property does not change when azobenzene is grafted to polymer or organic-inorganic hybrid materials, this provides a strong theoretical basis for the paper. The paper mainly focuses on photoresponsive materials containing azobenzene. Four photoresponsive azobenzene monomers and their polymers have been synthesized, the photoisomerization of the functional monomers and their polymers have been studied, and the effects of organic and inorganic framework on light-response rate have been also discussed. The detailed research contents are as follows:1. In chapter one, a short introduction to the azobenzene structure, types, preparation, photoisomerization and its mechanism, and then a brief review on research and application of azobenzene-based photo-responsive materials are given.2. In chapter two, through esterification, substitution etc, four azobenzene-based functional monomers have been synthesized with 4,4’-dihydroxyazobenzene as the starting material:4,4’-(2-methylacrylatyl) azobenzene (MAOAZO),4-methylacrylatyl-4’-hydroxyl-azobenzene (MAOAZOOH),4,4’-(3-triethoxysilylpropoxyl) azobenzene (TESPPAZO), and 4-(3-triethoxysilylpropoxyl)-4’-hydroxyl-azobenzene (TESPPAZOOH). The chemical structures of these founctional monomers have been characterized by 1H NMR,13C NMR, FT-IR, etc, and the photoisomerization of azobenzene compounds containing different substituents have been studied by UV-Vis spectrophotometer.3. In chapter three, a series of organic polymers containing azobenzene have been synthesized via free radical polymerization between azobenzene functional monomers and cross-linker (trimethylolpropane trimethacrylate (TRIM)) using azobisisobuty- ronitrile as the initiator. Their structures have been characterized by AFM, FT-IR, TG and N2 adsorption-desorption analysis. The photoisomerization of the organic polymers have been characterized by UV-Vis spectrophotometer, and the influence of the molar ratio between the functional monomer and cross-liner (TRIM) on the rate constants was discussed.4. In chapter four, a series of organic-inorganic hybrid materials containing azobenzene have been prepared by sol-gel method. The photoisomerization of organic-inorganic hybrid materials have been characterized by UV-Vis spectrophotometer, and the effects of the molar ratio between the organosilicone functional monomer and TEOS on the rate constants are also discussed. The structures of organic-inorganic hybrid materials have been characterized by AFM, FT-IR, TG and N2 adsorption-desorption analysis.5. In chapter five, the photoisomerization rate constants of the azobenzene-based functional monomers containing different substituents and the corresponding photoresponsive polymer materials have been studied.6. The last chapter summarized the main results and conclusions. Some recommendations for future work are given.