Light-induced mechanical response in crosslinked liquid-crystalline polymers with photoswitchable glass transition temperatures
Light-induced mechanical response in crosslinked liquid-crystalline polymers with photoswitchable glass transition temperatures
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DOI：
10.1038/s41467-018-05744-x
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发表时间：
2018-08
影响因子：
16.6
通讯作者：
Youfeng Yue;Y. Norikane;R. Azumi;E. Koyama
中科院分区：
文献类型：
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作者：
Youfeng Yue;Y. Norikane;R. Azumi;E. Koyama
光能转化为机械能在应用中具有根本的意义。特别是在纳米尺度上进行精细的分子设计，以实现宏观尺度上高效的光刻效应，已成为研究热点之一。在这里，通过将“光熔”偶氮苯单体交联到液晶（LC）网络中，我们生成了光响应聚合物薄膜，该薄膜在室温（~20°C）下具有可逆的光切换玻璃化转变温度（Tg），并在UV/可见光刺激下具有光电致动性。偶氮发色团的反式到顺式异构化导致交联LC聚合物的变化。聚合物网络的温度在变换型时高于室温，而在梭形时低于室温。我们证明了光开关对光机械弯曲的贡献，并提出了一种新的光机械弯曲机制，将这一过程归因于薄膜的不均匀变化。
Energy conversion of light into mechanical work is of fundamental interest in applications. In particular, diligent molecular design on nanoscale, in order to achieve efficient photomechanical effects on macroscopic scale, has become one of the most interesting study topics. Here, by incorporating a “photomelting” azobenzene monomer crosslinked into liquid crystalline (LC) networks, we generate photoresponsive polymer films that exhibit reversible photoswitchable glass transition temperatures (Tg) at room temperature (~20 °C) and photomechanical actuations under the stimulus of UV/visible light. Thetrans-to-cisisomerization of azo chromophores results in a change inTgof the crosslinked LC polymers. TheTgof the polymer network is higher than room temperature in thetrans-form and lower than room temperature in thecis-form. We demonstrate the photoswitchableTgcontribute to the photomechanical bending and a new mechanism for photomechanical bending that attributes the process to an inhomogeneous change inTgof the film is proposed.