Light-induced thermal deformation analysis in multilayer liquid crystal network actuators

This study systematically investigates the thermal, optical, and mechanical behavior of light-induced thermal actuation of liquid crystal network (LCN) actuators, focusing on the impact of cross-linking concentrations and stacking configurations. In this work, a modular, layer-by-layer fabrication method is developed to build multilayer LCN actuators with predictable and tunable actuation. By integrating twisted molecular alignment in each layer, this approach facilitates programmable actuation behavior and provides quantitative insight into optimizing actuation efficiency. Increasing volumetric thickness and varying crosslinking concentrations provided an understanding of the optimal multilayer configuration, which can be utilized for specific design applications. A combination of experimental results, which were supported by the finite element method (FEM), was conducted, providing a deeper understanding of the bending actuation under varying light intensities and thermal conditions. Moreover, force measurements of multilayer actuators confirm enhanced actuation output up to more than double the force produced by single-layer actuators. Furthermore, an improved analytical model was developed to predict the effect of multilayer on deformation amplitudes. This finding provides a fundamental framework for optimizing LCN actuators, advancing their application in smart materials, precision-controlled soft robotics, and adaptive structures.