Theory of Light‐Induced Deformation of Azobenzene Elastomers
Theory of Light‐Induced Deformation of Azobenzene Elastomers
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偶氮苯弹性体光致变形理论
DOI：
10.1002/masy.201250602
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发表时间：
2012
影响因子：
--
通讯作者：
G. Heinrich
中科院分区：
文献类型：
--
作者：
V. Toshchevikov;M. Saphiannikova;G. Heinrich
总结：提出了一种描述含偶氮生色团光敏弹性体光致变形的微观理论。我们使用取向方法，其中假定光致变形是由于偶氮苯发色团相对于线偏振光E的电矢量的重新取向引起的，这是由于trans-cis-trans光异构化过程，其效率取决于发色团相对于矢量E的取向。在高斯近似的网络链的弹性的框架中，它示出的光致变形的值取决于网络链的化学结构，即，在主链周围的发色团的取向分布，这是有关的间隔的长度和弹性。取决于化学结构，偶氮苯弹性体可以表现出沿着矢量E的膨胀或单轴收缩沿着，以及随着光强度增加的非单调变形（在小的光强度下膨胀，在高的光强度下收缩）。
Summary: A microscopic theory is proposed to describe light-induced deformation of photo-sensitive elastomers bearing azobenzene chromophores in their strands. We use an orientation approach in which it is assumed that the light-induced deformation is caused by reorientation of azobenzene chromophores with respect to the electric vector of the linearly polarized light, E, due to the trans-cis-trans photoisomerizaion process whose efficiency depends on the orientation of the chromophores with respect to the vector E. In the framework of the Gaussian approximation for elasticity of network strands it is shown that the value of the light-induced deformation depends on the chemical structure of network strands, namely, on the orientation distribution of chromophores around the main chains which is related to the length and elasticity of spacers. Depending on the chemical structure, azobenzene elastomers can demonstrate expansion or uniaxial contraction along the vector E, as well as non-monotonic deformation with increasing light intensity (expansion at small light intensities and contraction at high ones).