偶氮苯
光异构化
材料科学
侧链
中胚层
聚合物
光致变色
液晶
热致晶体
取代基
偶氮化合物
部分
高分子化学
异构化
光化学
有机化学
液晶
化学
复合材料
纳米技术
催化作用
光电子学
作者
Annino Sante Angeloni,Daniele Caretti,Carlo Carlini,Emo Chiellini,Giancarlo Galli,Angelina Altomare,Roberto Solaro,Michele Laus
标识
DOI:10.1080/02678298908033186
摘要
Abstract Two classes of thermotropic polymers were synthesized containing the trans-azobenzene unit as both a mesogenic and a photochromic group. In the former class (I) the azobenzene unit is incorporated into the main chain of substituted polymalonates, while in the latter class (II) it is appended as a side chain substituent to a polyacrylate backbone. The liquid-crystalline properties of the polymers were studied as a function of the chemical structure. All of the prepared polymers I have smectic phases. Polymers II are nematic and/or smectic, or cholesteric when including a chiral residue R'. Polymers I and II when radiated at 348 nm in chloroform solution undergo trans-to-cis isomerization of the azobenzene moiety. The calculated rate constants are comparable with those of low molar mass model compounds, and indicate that the macromolecular structure does not significantly affect the photoisomerization rate.
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