Vantomme Ghislaine, Gelebart Anne Helene, Broer Dirk J, Meijer E W
Institute for Complex Molecular Systems (ICMS), Technical University of Eindhoven; Department of Chemical Engineering and Chemistry, Laboratory of Macromolecular and Organic Chemistry, Technical University of Eindhoven.
Institute for Complex Molecular Systems (ICMS), Technical University of Eindhoven; Department of Chemical Engineering and Chemistry, Laboratory for Functional Organic Materials and Devices (SFD), Technical University of Eindhoven.
J Vis Exp. 2017 Sep 20(127):56266. doi: 10.3791/56266.
A strategy based on doped liquid crystalline networks is described to create mechanical self-sustained oscillations of plastic films under continuous light irradiation. The photo-excitation of dopants that can quickly dissipate light into heat, coupled with anisotropic thermal expansion and self-shadowing of the film, gives rise to the self-sustained deformation. The oscillations observed are influenced by the dimensions and the modulus of the film, and by the directionality and intensity of the light. The system developed offers applications in energy conversion and harvesting for soft-robotics and automated systems. The general method described here consists of creating free-standing liquid crystalline films and characterizing the mechanical and thermal effects observed. The molecular alignment is achieved using alignment layers (rubbed polyimide), commonly used in the display manufacturing industry. To obtain actuators with large deformation, the mesogens are aligned and polymerized in a splay/bend configuration, i.e., with the director of the liquid crystals (LCs) going gradually from planar to homeotropic through the film thickness. Upon irradiation, the mechanical and thermal oscillations obtained are monitored with a high-speed camera. The results are further quantified by image analysis using an image processing program.
本文描述了一种基于掺杂液晶网络的策略，用于在连续光照下使塑料薄膜产生机械自持振荡。能够迅速将光耗散为热的掺杂剂的光激发，与薄膜的各向异性热膨胀和自遮挡相结合，导致了自持变形。观察到的振荡受薄膜尺寸、模量以及光的方向性和强度影响。所开发的系统在软机器人和自动化系统的能量转换与收集方面具有应用前景。这里描述的通用方法包括制备独立的液晶薄膜，并对观察到的机械和热效应进行表征。分子取向通过在显示制造行业常用的取向层（摩擦聚酰亚胺）来实现。为了获得具有大变形的致动器，液晶元以展曲/弯曲构型排列并聚合，即液晶（LC）的指向矢在薄膜厚度方向上从平面逐渐变为垂直排列。光照时，用高速相机监测获得的机械和热振荡。结果通过使用图像处理程序的图像分析进一步量化。
