NIR-Vis-UV Light-Responsive Actuator Films of Polymer-Dispersed Liquid Crystal/Graphene Oxide Nanocomposites
NIR-Vis-UV Light-Responsive Actuator Films of Polymer-Dispersed Liquid Crystal/Graphene Oxide Nanocomposites
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DOI：
10.1021/acsami.5b09676
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发表时间：
2015-12-16
影响因子：
9.5
通讯作者：
Yu, Haifeng
中科院分区：
文献类型：
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作者：
Cheng, Zhangxiang;Wang, Tianjie;Yu, Haifeng
为了充分利用光机械材料的太阳光，制备了聚合物分散液晶（PDLC）/氧化石墨烯（GO）纳米复合材料的近红外-可见光响应致动器薄膜。该策略基于 PDLC/GO 纳米复合材料中光化学和光热过程相结合引起的液晶从向列相到各向同性相的相变。在对薄膜进行机械拉伸时，分离的液晶域中会发生拓扑形状变化和介晶排列，从而使薄膜能够响应近红外-可见-紫外光。均匀分散的 GO 薄片充当光吸收剂和纳米级热源，将近红外或可见光转化为热能，加热薄膜并光热诱导液晶微域的相变。通过利用紫外光照射下液晶的光化学相变，将一种偶氮苯染料掺入液晶域中，赋予纳米复合薄膜具有紫外响应特性。此外，通过调整机械处理时的伸长率可以很好地控制光响应行为。近红外-可见-紫外光响应的PDLC/GO纳米复合薄膜具有易于制造、低成本、良好的成膜和机械特性等优异性能，有望在阳光直接驱动的软执行器和光机械系统领域得到广泛应用。
To take full advantage of sunlight for photomechanical materials, NIR-vis-UV light-responsive actuator films of polymer-dispersed liquid crystal (PDLC)/graphene oxide (GO) nanocomposites were fabricated. The strategy is based on phase transition of LCs from nematic to isotropic phase induced by combination of photochemical and photothermal processes in the PDLC/GO nanocomposites. Upon mechanical stretching of the film, both topological shape change and mesogenic alignment occurred in the separated LC domains, enabling the film to respond to NIR-vis-UV light. The homodispersed GO flakes act as photoabsorbent and nanoscale heat source to transfer NIR or VIS light into thermal energy, heating the film and photothermally inducing phase transition of LC microdomains. By utilizing photochemical phase transition of LCs upon UV-light irradiation, one azobenzene dye was incorporated into the LC domains, endowing the nanocomposite films with UV-responsive property. Moreover, the light-responsive behaviors can be well-controlled by adjusting the elongation ratio upon mechanical treatment. The NIR-vis-UV light-responsive PDLC/GO nanocomposite films exhibit excellent properties of easy fabrication, low-cost, and good film-forming and mechanical features, promising their numerous applications in the field of soft actuators and optomechanical systems driven directly by sunlight.