Liquid crystal polymer actuators with complex and multiple actuations

Abstract

Deformable liquid crystal polymers (LCPs), which possess both entropic elasticity of polymer networks and anisotropic property originating from ordered mesogens, gain more and more interests for use as biomedical soft actuators. Especially, the LCP actuators with controllable mesogen alignment, sophisticated geometry and reprogrammability are a rising star on the horizon of soft actuators, since they enable complex and multiple actuations.This review focuses on two topics: 1) the regulation of mesogen alignment and geometry of LCP actuators for complex actuations; 2) the newly designed reprogrammable LCP materials for multiple actuations. First, basic actuation mechanisms are briefly introduced. Then, LCP actuators with complex actuations are demonstrated. Special attention is devoted to the improvement of fabrication methods, which profoundly influence the available complexity of the mesogen alignment and geometry. Subsequently, reprogrammable LCP actuators featuring dynamic networks or shape memory effect are exhibited, with the emphasis on their multiple actuations. Finally, perspectives on the current challenges and potential development trends toward more intelligent LCP actuators are discussed, which may shed light on future investigations in this field.