Title: Photo- and Humidity-Responsive Liquid Crystal Copolymer Actuators Fabricated via Vapor-Assisted Alignment

AuthorHaozhe Sun, Xingpeng Chai, Haipeng Yang, Jia Wei*, Yanlei Yu*

Journal: ACS Appl. Mater. Interfaces 2024, 16, 15405−15415

Abstract:

Deformable liquid crystal polymers (LCPs) driven by more than one external stimulus have received extensive attention in fields ranging from multifunctional soft robots to bionic actuators. Combining responsive liquid crystal with nonmesogenic responsive groups within polymer offers a versatile way to obtain multiresponsive LCPs. However, the incorporation of nonmesogenic responsive groups causes interruption in the assembly of mesogens and brings a challenge to the alignment of LCPs. Herein, a new method is put forward to facilitate uniform mesogen alignment by exerting water vapor in the film preparation process. Using this method, vapor-assisted alignment, the homeotropic alignment of azobenzene mesogens is achieved in a copolymer containing nonmesogenic poly(ethylene glycol) (PEG). The obtained copolymer films present photodeformation brought by azobenzene isomerization and humidity-responsive deformation resulting from the asymmetric swelling of film surfaces. The dual-responsive smart “blinds” and bionic flower actuators are fabricated to demonstrate the integration of the two different stimuli. This work is anticipated to provide a feasible alignment method for multiresponsive LCPs, showing the potential applications in soft robots, sensors, and biomimetic devices.

论文链接:https://pubs.acs.org/doi/10.1021/acsami.4c01809

PDF下载:Photo- and Humidity-Responsive Liquid Crystal Copolymer Actuators Fabricated via Vapor-Assisted Alignment.pdf

  多刺激驱动的形变液晶聚合物在多功能软机器人及仿生执行器领域具有应用潜力。将刺激响应性的液晶基元与非液晶基元组合为多刺激响应液晶聚合物的获得提供了更多的机遇。然而,非液晶基元的引入会扰乱液晶基元的排列,使得液晶聚合物不易形成有序结构。在本工作中,我们运用一种新的取向方法实现共聚物体系中液晶基元的有序排列,即在偶氮苯与聚乙二醇的共聚物的成膜过程中施加蒸汽。结果表明,这种蒸汽辅助取向的策略促进了薄膜中液晶基元的垂直取向,成功实现了含有非液晶性基团的聚环辛烯类液晶聚合物的有序组装和光/湿度双响应形变。在此基础上,我们构筑了智能窗帘、仿生花朵和仿生藤蔓等双响应执行器。我们希望这种蒸汽诱导取向的策略能为制备多响应液晶共聚物提供新的设计思路。