Wang Yuchen, Dang Alei, Zhang Zhifeng, Yin Rui, Gao Yuchong, Feng Liang, Yang Shu
Department of Materials Science and Engineering, University of Pennsylvania, 3231 Walnut Street, Philadelphia, PA, 19104, USA.
School of Materials Science and Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, 710072, P. R. China.
Adv Mater. 2020 Nov;32(46):e2004270. doi: 10.1002/adma.202004270. Epub 2020 Oct 12.
Liquid crystal elastomers (LCEs) are of interest for applications such as soft robotics and shape-morphing devices. Among the different actuation mechanisms, light offers advantages such as spatial and local control of actuation via the photothermal effect. However, the unwanted aggregation of the light-absorbing nanoparticles in the LCE matrix will limit the photothermal response speed, actuation performance, and repeatability. Herein, a near-infrared-responsive LCE composite consisting of up to 0.20 wt% poly(ethylene glycol)-modified gold nanorods (AuNRs) without apparent aggregation is demonstrated. The high Young's modulus, 20.3 MPa, and excellent photothermal performance render repeated and fast actuation of the films (actuation within 5 s and recovery in 2 s) when exposed to 800 nm light at an average output power of ≈1.0 W cm , while maintaining a large actuation strain (56%). Further, it is shown that the same sheet of AuNR/LCE film (100 µm thick) can be morphed into different shapes simply by varying the motifs of the photomasks.
液晶弹性体（LCEs）在软机器人和形状变形装置等应用中具有吸引力。在不同的驱动机制中，光具有通过光热效应实现驱动的空间和局部控制等优点。然而，光吸收纳米颗粒在LCE基质中不必要的聚集会限制光热响应速度、驱动性能和可重复性。在此，展示了一种由高达0.20 wt%的聚乙二醇修饰的金纳米棒（AuNRs）组成且无明显聚集的近红外响应LCE复合材料。当以≈1.0 W cm的平均输出功率暴露于800 nm光时，高杨氏模量（20.3 MPa）和优异的光热性能使薄膜能够重复快速驱动（5秒内驱动，2秒内恢复），同时保持较大的驱动应变（56%）。此外，研究表明，仅通过改变光掩模的图案，同一片AuNR/LCE薄膜（100 µm厚）就能变形为不同形状。
