Light-induced reversible volume changes in thin films of azo polymers : The photomechanical effect
Light-induced reversible volume changes in thin films of azo polymers : The photomechanical effect
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DOI：
10.1021/ma051564w
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发表时间：
2005-11
期刊：
影响因子：
5.5
通讯作者：
Oleh M. Tanchak;C. Barrett
中科院分区：
文献类型：
--
作者：
Oleh M. Tanchak;C. Barrett
用单波长椭圆偏振法对含偶氮苯生色团的聚合物薄膜的光致膨胀进行了真实的实时表征。发现偶氮聚合物膜的初始膨胀是不可逆的，在厚度范围为250 - 1400埃的膜中观察到的相对膨胀程度为1.5-4%。随后的和可逆的膨胀观察到重复的照射循环，实现0.6- 1.6%的相对程度的膨胀。通过改变泵浦光束功率或照射持续时间来控制这种可逆膨胀的程度，使这些聚合物能够用作可逆的光机械材料。
A light-induced expansion of thin films of polymers containing azobenzene chromophores was characterized in real time by single wavelength ellipsometry. An initial expansion of the azo polymer films was found to be irreversible with an extent of relative expansion observed of 1.5-4% in films of thickness ranging from 250 to 1400 A. A subsequent and reversible expansion was observed with repeated irradiation cycles, achieving a relative extent of expansion of 0.6-1.6%. Control over the extent of this reversible expansion was achieved by varying the pump beam power or irradiation duration, allowing these polymers to function as reversible photomechanical materials.