【作者】 俞小伍；

【导师】 张其锦；

【作者基本信息】 中国科学技术大学 ， 高分子化学与物理， 2008， 博士

【摘要】 本论文通过改变间隔基长度和偶氮苯环取代基以及连接方式的方法，将光响应性偶氮生色团引入聚二乙炔。合成表征了几个系列偶氮功能化的聚二乙炔，并对它们的非线性光学和热致色变性质进行了详细地研究。主要工作内容如下：1．介绍了聚二乙炔的聚合机理和色变机理，并综述了聚二乙炔化合物的研究及应用现状。2．成功地合成了含偶氮苯生色团侧链的聚{[CH₃-（CH₂）₁₁-C≡C-C≡C-（CH₂）₈-COO -（CH₂）₂-O-C₆H₄-N=N-C₆H₄-R]，R=NO₂，CN，CH₃分别代表3a,3b,3c}，这些聚二乙炔不溶于常见的有机溶剂且具有良好的热稳定性（≥285℃）。使用紫外可见光谱，拉曼光谱，X射线衍射对所得聚合物的热致色变性质进行了研究，结果显示所有的聚合物都显示出较低的红相低临界温度和较高的红相高临界温度。P3a,P3a,P3c的红相临界温度范围分别为60～160℃，57～162℃和50～154℃，比目前文献报道的可逆热致色变的温度范围宽。3．通过金属氧化偶联的方法成功合成了一系列主链含二乙炔基团的主链偶氮聚合物{-[C≡C-CH₂-O-C₆H₄-OCO-（CH₂）_m-O-C₆H₄-N=N-C₆H₄-O-（CH₂）_m- OCO- C₆H₄-O-CH₂-C≡C]_n^-，m=3，6，11}。研究了它们的热交联性能，它们都能通过二乙炔基团的热聚合得到交联的偶氮聚合物。使用13纳秒的Nd：YAG激光系统在532nm下测试了所得交联偶氮聚合物的三阶非线性性能。结果显示，这些交联偶氮聚合物的三阶非线性系数可达10^-9esu，且间隔基长度非线性对光学性能有一定的影响。长的间隔基长度会降低非线性光学性能。4．设计和合成了一系列主链含二乙炔基团的侧链偶氮聚合物{-[C≡C-CH₂-O- C₆H₄-OCO-C₂H₄-O-（N-C₆H₄-N=N-C₆H₄-R）-O-C₂H₄-OCO-C₆H₄-O-CH₂-C≡C]_n-，R=NO₂，OCH₃}。这些聚合物都可通过二乙炔基团的热聚合物得到交联的偶氮聚合物，随加热时间延长，紫外可见吸收光谱中偶氮生色团吸收峰位置逐渐蓝移。我们根据蓝移程度定义了一种表观交联度。使用He-Cd激光系统在442nm下测试了所得交联偶氮聚合物的光致双折射并尝试刻制偶氮聚合物光栅。我们发现，聚合物薄膜的光致双折射随交联度增加而减小，由此实现了对光致双折射的控制。我们分别用强度调制和偏振调制两种方法在偶氮聚合物薄膜上刻写光栅，结果发现，强度调制模式不能写入光栅，而偏振调制模式可得到纯折射率的光栅，其一级衍射效率在15分钟内达到～1．70×10^-2。通过反复“写入-擦除”实验，证明交联可明显提高两种偶氮聚合物光致双折射的稳定性。5．制备了一系列聚（10，12-二十五碳双炔酸）／含二乙炔基团主链偶氮聚合物（PDA／PAzo6）和聚（10，12-二十五碳双炔酸）／聚甲基丙烯酸甲酯（PDA／PMMA）复合物薄膜。紫外吸收光谱测试表明，PDA／PAzo6薄膜最大吸收峰位于663nm，较一般PDA高出～30nm。通过TEM和XRD分析，与PDA在PMMA以及本体PDA的聚集态和晶型比较，PDA在PAzo6中的聚集状态及晶型明显的变化。我们认为正是由于聚集态和晶型变化使得其最大吸收峰位置发生了红移。另外，PDA／PAzo6薄膜还显示出新颖的热致色变和光致变色性质，详细的机理有待进一步研究。更多还原

【Abstract】 Several sets of novel polydiacetylenes bearing photoactive azobenzene chromophores were synthesized and characterized, which are difference in alkylene spacer and the substituents of azobenzene ring or connecting modes. In the thesis, the nonlinear optical properties and the thermochromism of the azobenzene functional polydiacetylenes were investigated detailedly. The main contents of this dissertation consist of the following points:1. The mechanism of polymerization of the diacetylenic compounds and the mechanism of chromic properties of polydiacetylenes were presented, and the recent development of the research and the application on polyacetylenes were reviewed systematically.2. A series of polydiacetylenes containing azobenzene chromophores with different terminal groups poly-{CH₃-（CH₂）₁₁-C≡C-C≡C-（CH₂）₈-COO-（CH₂）₂-O-C₆H₄-N= N-C₆H₄-R, where R = NO₂, CN, CH₃ and labeled as 3a, 3b and 3c, respectively} were synthesized. The polymers were no longer soluble in common organic solvents and thermally stable （≥285℃）. The thermochromic behavior of the polymers was evaluated with UV, Raman, X-ray diffraction analyses, it was found from results that all of the polymers possessed large temperature ranges of thermochromism. The temperature ranges between the low and the high critical temperature for the red phase were obtained to be 60-160℃, 57-162℃and 50-154℃for P3a, P3b and P3c, respectively, which are larger than those reported before for other polydiacetylenes.3. A series of main chain azobenzene polymers containing diacetylene moieties with different lengths of the spacer {-[C≡C-CH₂-O-C₆H₄-OCO-（CH₂）_m-O-C₆H₄-N=N-C₆H₄-O-（CH₂）_m-OCO-C₆H₄-O-CH₂-C≡C]_n^-, where m = 3, 6, 11} were synthesized by oxidative coupling polymerization. All the polymers could be cross-linked at the elevated temperatures due to the polymerization reactions of the diacetylene groups in the polymer backbone, and the cross-linked polymers showed dramatically modified properties, such as their thermal stability and solvent resistance. The third-order nonlinear susceptibilities of the cross-linked polymers were investigated by an 13 ns Nd:YAG laser system at 532 nm wavelength. Results showed that the third-order nonlinear susceptibility of the polymers was as high as 10^-9 esu and the optical limiting and nonlinear optical performances were affected by the spacer length .The polymers having longer spacer lengths on the azobenzene ring show inferior properties.4.A series of azopolymers{-[C≡C-CH₂-O-C₆H₄-OCO-C₂H₄-O-（N-C₆H₄-N=N-C₆H₄-R）-O-C₂H₄- OCO- C₆H₄ -O-CH₂-C≡C]_n^-, R = NO₂, OCH₃} with diacetylene main chain and azobenzene side moieties were prepared by oxidative coupling polymerization. It was found that the optical absorption of azobenzene showed a gradually shifting to blue with development of the thermal curing reaction, and based on that, we defined an apparent cross-linking degree. The photo-induced birefringence （Δn） and grating of the cross-linked polymers were evaluated by a He-Cd laser system at 442 nm wavelength. We also found that the maximum value ofΔn increased with a decreasing in the cross-linking degree, and when two parallel linearly polarized beams at 442 nm were interfered in the film, no diffraction beam was observed. However, when two orthogonal linearly polarized beams were allowed to interfere in the film, a polarization grating was formed and the value of diffraction efficiency reached about -1.70×10^-2 within 15 min. The repeated "writing" and "erasing" experiments were made and the value of maximum transmittance kept constant for cross-linked films, which indicated that cross-linking could effectively improve the stability of the photo-induced birefringence in the new materials.5.A series of poly-（pentacosa-10,12-diynoic acid）/diacetylene-containing mainchain azopolymer（PDA/PAzo6） and poly-（pentacosa-10, 12-diynoic acid） /polymethy lmethacrylate（PDA/PMMA） hybrid films were prepared. The photo-polymerization of films was carried out by irradiation at 254 nm under monitoring the optical absorption in the visible region. It was found that PDA/PAzo6 showed maximum absorption at 663 nm, which was 30 nm higher than that of PDA/PMMA. Through the TEM and XRD analyses, we proposaled the obviously red-shift of absorption maximum in visible region came of the phase-separated domains of PDA/PAzo6. In addition, the PDA/PAzo6 showed unusual thermochromism and interesting photochromism, Investigation into thermochromism and photochromism of these novel materials were in progress.更多还原