A color-changing plasmonic actuator based on silver nanoparticle array/liquid crystalline elastomer nanocomposites

Abstract

Inspired by the chameleon and cephalopod, scientists have developed materials and devices to mimic the ability to change skin color with an environmental stimulus. However, a complicated integration of stretch ability, color changing and stimulus sensing is commonly required. Herein, by integrating a single-layer silver nanoparticles (Ag NPs) array with a liquid crystal elastomer (LCE), we develop a facile bilayer-structural device that exhibits the ability to change color with thermally-driven actuation behavior. This indicates that an Ag NPs array inlayed into the surface of a LCE layer could spontaneously induce a homeotropic orientation of LC molecules, thereby allowing for different deformations associated with the blue-shift of structural color at vertical and hybrid alignment states in bilayer-structural films. The observed blue-shift of the localized surface plasmon resonance (LSPR) peak which derives from a close packed Ag NPs array may be connected to the elongation of the gap distances of Ag NPs induced by flat expansion and bent deformation of the LCE. Moreover, finite-element simulations are undertaken to understand the intrinsic mechanism of the above behavior. The developed color-changing actuators could be promising candidates for smart environmental-responsive devices such as thermal-camouflage skin and color-changing actuators.