Additive Manufacturing of Liquid Crystal Elastomer Actuators Based on Knitting Technology

Abstract

Liquid crystal elastomer (LCE) exhibits large and reversible deformability originating from the alignment of liquid crystal mesogens. Additive manufacturing provides high controllability in the alignment and shaping process of LCE actuators. However, it still remains a challenge to customize LCE actuators with both diverse 3D deformability and recyclability. In this study, a new strategy is developed to exploit knitting technique to additively manufacture LCE actuators. The obtained LCE actuators are fabric‐structured with designed geometry and deformability. By accurately adjusting the parameters of the knitting patterns as modules, diverse geometry is pixel‐wise designed, and complex 3D deformations including bending, twisting, and folding are quantitatively controlled. In addition, the fabric‐structured LCE actuators can be threaded, stitched, and reknitted to achieve advanced geometry, integrated multi‐functions and efficient recyclability. This approach allows the fabrication of versatile LCE actuators with potential applications in smart textiles and soft robots.

Soft Fiber/Textile Actuators: From Design Strategies to Diverse Applications

“…Textile actuator implementation typically occurs in two ways: one is sewing stimulus-responsive fibers into everyday textiles, 53,54 and the other is weaving or knitting fiber actuators directly into fabrics. 57 As examples, Figure 3a demonstrates how active liquid crystal elastomer (LCE) yarns, combined with conventional textile yarns, produce textiles capable of contract/relax and 3D deformations. 55 Figure 3b shows that the treated magnetically responsive fiber was woven directly into textiles, which could rotate, roll, and fold/unfold when stimulated by a magnetic field.…”

“…Magnetic fibers can also be integrated into daily textiles for rehabilitation equipment (Figure c). Figure d illustrates the fabrication process of an actuator with knitted structures . Regulating the torque in LCE fibers within knitted textiles enables the actuator to perform various deformations (Figure e).…”

“…(d) The fabrication process of the plain knitted fabric, and (e) spiral twisting, origami folding, and threading deformation of the fabric actuator. Reproduced with permission from ref . Copyright 2023 John Wiley and Sons.…”

“…Figure 3d illustrates the fabrication process of an actuator with knitted structures. 57 Regulating the torque in LCE fibers within knitted textiles enables the actuator to perform various deformations (Figure 3e). In brief, processing fibers into yarns and yarns into textiles enhances the actuator's versatility regarding its structure, mechanics, and applications.…”

Multimode opto-magnetic dual-responsive actuating fibers and fabrics programmed via direct ink writing

“…Firstly, actuating fibers can be seamlessly integrated with passive textiles to fabricate smart textiles, 15 or be interwoven to construct fabrics with enhanced actuation modes. 16 Secondly, the incorporation of an additional actuation dimension, namely magnetic actuation, augments the diversity of motion patterns in both actuating fibers and fabrics.…”