Well-Defined Liquid-Crystalline Diblock Copolymers with an Azobenzene Moiety: Synthesis, Photoinduced Alignment and their Holographic Properties
Well-Defined Liquid-Crystalline Diblock Copolymers with an Azobenzene Moiety: Synthesis, Photoinduced Alignment and their Holographic Properties
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DOI：
10.1021/ma801077g
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发表时间：
2008-10
期刊：
影响因子：
5.5
通讯作者：
Haifeng Yu;Y. Naka;A. Shishido;T. Ikeda
中科院分区：
文献类型：
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作者：
Haifeng Yu;Y. Naka;A. Shishido;T. Ikeda
采用原子转移自由基聚合（ATRP）方法合成了一系列侧链含偶氮苯的液晶嵌段共聚物。使用溴封端的聚（甲基丙烯酸甲酯）作为大分子引发剂，得到的两嵌段共聚物显示出明确的结构和窄的分子量分布。微相分离的纳米结构与介晶块在连续或分离相观察。由于嵌段共聚物中液晶基元含量的不同，它们表现出不同的光致取向和全息记录行为。嵌段共聚物与偶氮苯在大多数阶段表现出类似的性能的光致取向和折射率调制含偶氮苯的均聚物，但它们的光致质量传输被部分抑制的微相分离，导致较低的表面浮雕比的均聚物。嵌段共聚物中的光诱导传质被大大抑制。
A series of liquid-crystalline (LC) diblock copolymers with an azobenzene moiety in the side chain were prepared by atom transfer radical polymerization (ATRP). Using a bromo-terminated poly(methyl methacrylate) as a macroinitiator, the obtained diblock copolymers showed well-defined structures and narrow molecular-weight distributions. Microphase-separated nanostructures with mesogenic blocks in either continuous or separated phases were observed. Owing to varied content of mesogens in the block copolymers, they showed different behavior of photoinduced alignment and holographic recording. Block copolymers with azobenzenes in the majority phases exhibited a similar performance of photoinduced alignment and refractive-index modulation to the azobenzene-containing homopolymer, but their photoinduced mass transportation was partly suppressed by the microphase separation, leading to a lower surface relief than that of the homopolymer. The photoinduced mass transfer was greatly prohibited in the block copolym...