Liquid Crystal Polymer‐Based Soft Robots

Abstract

Soft robots outperform the conventional robots on enhanced safety for human-machine interaction, environmental adaptability, and continuous deformation. In this blooming area of fundamental and technological importance, liquid crystal polymer networks and liquid crystal elastomers (referred to as LCNs) have emerged as one of the most valuable candidates for soft robots due to their complex, large, and reversible shape change capabilities. To date, much research effort, mainly regarding chemical synthesis, fabrication technologies and soft robot design, has been dedicated to LCN robotic systems to endow them with versatile and complex actions controlled by various stimuli. Herein, starting with the principle that governs the stimuli-responsiveness of LCNs, recent progress made in LCN soft robots is summarized while focusing on different robotic motions, such as grapping, walking, swimming, and oscillation. Especially, novel LCNs with intelligent functions such as reprocessability, reconfigurability, self-regulating behavior and associative learning capability, are highlighted. This article aims to provide significant insights into the design and development of LCN-based soft robots.

Robust and Reprocessable Artificial Muscles Based on Liquid Crystal Elastomers with Dynamic Thiourea Bonds

“…[10][11][12] Moreover, the anisotropic mechanical properties of the LCEs can be harnessed to program their shape changes, enabling complex deformations including bending, coiling, twisting, and helixing. [3,13,14] Recently, significant progress has been achieved in the field of LCEs for materials synthesis, [15][16][17][18][19] fabrication, [16,[20][21][22][23][24] and expansion of LCE applications., [25][26][27][28][29][30][31] which has led to the renaissance of LCEs from both scientific and engineering aspects. However, the preparation of LCEs as actuators typically requires mesogen alignment prior to cross-linking, which leads to complicated fabrication processes unlike those required for fabricating conventional elastomers.…”

Soft Actuator Materials for Electrically Driven Haptic Interfaces

“…This indirect heating strategy allows for the localized and efficient temperature control of the polymer system, where the actuation can be precisely controlled in larger LCE systems. [ 94 ]…”

Light-Actuated Liquid Crystal Elastomer Prepared by Projection Display

“…As a type of ordered crosslinked polymer, liquid crystal elastomers (LCEs) have shown remarkable structural transformations by patterning the complex molecular orientations [ 7 ]. The change in the molecular ordering of LCE under external stimuli such as light [ 8 ], heat [ 9 ], or humidity [ 10 ] gives rise to a variety of three-dimensional (3D) shape morphs thanks to its anisotropic elasticity [ 11 , 12 , 13 ]. For example, Ware et al demonstrated arrays of cones and anti-cones transformed from a flat LCE film by pixelating its two-dimensional (2D) director field [ 14 ].…”