Seamless multimaterial 3D liquid-crystalline elastomer actuators for next-generation entirely soft robots

Abstract

Liquid-crystalline elastomers (LCEs) are excellent soft actuator materials for a wide range of applications, especially the blooming area of soft robotics. For entirely soft LCE robots to exhibit high dexterity and complicated performance, several components are typically required to be integrated together in one single robot body. Here, we show that seamless multicomponent/multimaterial three-dimensional (3D) LCE robots can be created via simultaneously welding and aligning LCE materials with different chemical compositions and physical properties without other additives such as tapes and glues (just like metal welding). Both welding and aligning of the LCE materials rely on thermal polymerization of preformed LCE films with reactive acrylate groups. This method provides an easy way to robustly fabricate arbitrary 3D desirable geometries with strongly stable reversible actuations and multifunctionalities, which greatly enlarges and benefits the future applications and manufacturing of LCE soft robots.

Liquid Crystal Polymer‐Based Soft Robots

“…[ 116 ] Recently, researchers also exploited dynamic exchangeable bonds to allow various LCN actuators with different components and/or LC alignments to be welded/assembled into one system to fabricate complex soft robots. [ 117,118 ]…”

“…Therefore, the facile, robust and even seamless assembly strategy is also important for constructing strong and entirely soft robotic systems. [ 117 ]…”

Effect of Isomeric Amine Chain Extenders and Crosslink Density on the Properties of Liquid Crystal Elastomers

“…In addition, the shape change of LCEs can be effectively manipulated by a spatial control of the director profile that enables complex shape changes even when the LCE is compositionally homogenous [5,6]. These unique characteristics of LCEs promote their utilization as interesting components for developing various types of smart materials and systems, including artificial muscles [7,8], soft robots [9,10], smart coatings [11], and optical [12] and biomedical devices [13].…”

Desynchronized Liquid Crystalline Network Actuators with Deformation Reversal Capability

“…By adjusting the alignment of mesogens and/or the distribution of crosslinking domains, monolithic LCNs can display a wide range of predesignated deformations, including those based on contraction/extension, bending, twisting and their various possible combinations [11][12][13][14][15][16][17][18][19] . Accordingly, a myriad of complex shapes (e.g., wave, accordion, helix, saddle shapes, periodical patterns and 3D pro les of Gaussian curvatures) [20][21][22][23][24][25][26][27][28][29] as well as robotic and bionic motions (e.g., gripping, rolling, walking, swimming and oscillating) [30][31][32][33][34][35][36][37][38][39][40] have been achieved, making the eld ourish. Up to date, the reversible shape change of LCNs only involves two shapes corresponding to the isotropic state (disordered state) and the LC phase (ordered state), respectively.…”