Photochemical control of network structure in gels and photo-induced changes in their viscoelastic properties
Photochemical control of network structure in gels and photo-induced changes in their viscoelastic properties
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DOI：
10.1016/j.colsurfb.2007.01.020
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发表时间：
2007-04-15
影响因子：
5.8
通讯作者：
Horie, Kazuyuki
中科院分区：
文献类型：
--
作者：
Hosono, Nobuhiko;Furukawa, Hidemitsu;Horie, Kazuyuki
合成了主链含光敏偶氮基团的聚酰胺-酸凝胶，并通过动态粘弹性测量研究了其光辐照前后的粘弹性能。结果发现，405 nm的光诱导的局部体积变化和两倍增加的储能模量的凝胶。我们讨论了光照射后的储能模量的变化相当简单的经典橡胶弹性理论，这不能解释这种大的储能模量的增加。储能模量的光诱导增加可能是由于固定在网络结构中的拓扑约束的缠结相互作用的增加，由偶氮苯部分的光异构化引起。我们建议通过光照射实现凝胶网络结构中的拓扑约束，并计算由此产生的凝胶网络中的滑移链接比（拓扑约束的指数）。(c)2007 Elsevier B. V.保留所有权利。
Poly(amide acid) gels containing photosensitive azobenzene groups in the main chain have been synthesized and their viscoelastic properties before and after light irradiation have been investigated by dynamic viscoelasticity measurements. It was found that 405 nm light induced a local volume change and a two-fold increase in the storage modulus of the gels. We discuss the change in storage modulus upon light irradiation quite simply in terms of classical rubber elasticity theory, which cannot explain this large increase in storage modulus. The photo-induced increase in storage modulus may result from an increase in entanglement interactions of topological constraints fixed in the network structure, caused by photoisomerization of the azobenzene moieties. We suggest that topological constraints in the network structure of the gels were realized by light irradiation and calculate the resulting slip link ratio (index of the topological constraints) in the gel network. (c) 2007 Elsevier B.V. All rights reserved.