Gel formation and photoactive properties of azobenzene-containing polymer in liquid crystal mixture
Gel formation and photoactive properties of azobenzene-containing polymer in liquid crystal mixture
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DOI：
10.1007/s00396-010-2264-0
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发表时间：
2010-07
影响因子：
2.4
通讯作者：
A. Bobrovsky;V. Shibaev;V. Hamplová;M. Kaspar;M. Glogarová
中科院分区：
文献类型：
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作者：
A. Bobrovsky;V. Shibaev;V. Hamplová;M. Kaspar;M. Glogarová
首次将含有偶氮苯的光致变色液晶(LC)丙烯酸聚合物用于凝胶化低摩尔质量向列相混合物(LMNM)。在120°C(各向同性状态)下，LC聚合物在LMNM中溶解，仅有2.5wt.%的量，然后冷却，形成类固体光致变色LC凝胶。凝胶化与相分离和微尺度LC聚合物结构域的形成有关，这些结构域形成了一个包含被封装的向列相主体的物理“网络”。分析了混合物在凝胶形成过程中的质构变化，并测量了吸收光谱。重点研究了凝胶中偶氮苯侧基的光诱导E-Z异构化和Z-E异构化动力学。结果表明，紫外光(UV)照射和E-Z异构化过程伴随着偶氮苯部分H-聚集体的断裂和聚合物的部分溶解。
For the first time, a photochromic azobenzene-containing liquid crystalline (LC) acrylic polymer was used for gelation of low-molar-mass nematic mixture (LMNM). Dissolution of LC polymer in amount of only 2.5 wt.% in LMNM at 120°C (isotropic state) followed by cooling down results in formation of the solid-like photochromic LC gel. Gelation is associated with a phase separation and formation of microsized LC polymer domains, which form a physical “network” containing encapsulated nematic host. Textural changes of mixture during gel formation were analyzed, and absorbance spectra were measured. A special attention was paid to the kinetic study of photoinduced E-Z and Z-E isomerization of azobenzene side groups of polymer in gel. It was shown that ultraviolet (UV)-irradiation and E-Z isomerization processes are accompanied by disruption of H-aggregates of azobenzene moieties and partial dissolution of polymer.