Intelligent Polymer‐Based Bioinspired Actuators: From Monofunction to Multifunction

Abstract

tions from planar sheets to helix, cylinder and coil induced by through-the-thickness strain gradients. Reproduced with permission. [52] Copyright 2017, American Chemical Society. b) Shape transformations from planar sheets to cap and saddle induced by in-plane strain gradients. Scale bars: 10 mm. Reproduced with permission. [57] Copyright 2019, Nature Publishing Group. c) Shape transformations from planar sheets to programmable 3D configurations such as Randlett's flapping bird assisted by origami design principles. Reproduced with permission. [62] Copyright 2012, John Wiley & Sons. d) Shape transformations from planar sheets to programmable 3D configurations such as Enneper's surfaces assisted by patterning strategies. Reproduced with permission. [66] Copyright 2014, American Association for the Advancement of Science. e) Shape transformations from planar sheets to programmable 3D configurations such as Dendrobium helix assisted by biomimetic 4D printing. Scale bars: 5 mm. Reproduced with permission. [68] Copyright 2016, Nature Publishing Group. f) Inside-out reversible shape transformations mimicking the opening/closing of flowers induced by both through-the-thickness and in-plane strain gradients. Scale bars: 1 cm. Reproduced with permission.

Plant-Morphing Strategies and Plant-Inspired Soft Actuators Fabricated by Biomimetic Four-Dimensional Printing: A Review

“…These works are often accomplished prior to the 3D printing process. However, there is an alternative approach that allows for local anisotropic actuation as well-the selection and manipulation of multiple stimuli (Lee and Fang, 2012;Deng et al, 2018;Cui et al, 2019Cui et al, , 2020. Kotikian et al (2019) printed untethered soft robotic matter that allows repeated shaping and self-propulsion in response to external stimuli.…”

Recent advances in colour-tunable soft actuators

“…Compared to actuators built with rigid materials, soft actuators usually made of hydrogels, 6,7 shape memory polymers, 8,9 and liquid crystal elastomers 10,11 possess high levels of flexibility and freedom in deformation/ locomotion for better adaption to external environments, making them particularly promising in the broad field of applications. [12][13][14] With the assistance of precise structural design (e.g., bilayer, patterned structural design) and/or advanced manufacturing techniques (e.g., three-dimensional (3D) or four-dimensional (4D) printing), soft actuators can even achieve programmable deformations and locomotion highly resembling the natural actuating behaviours of creatures. [15][16][17] To enable soft actuators perform complex tasks in everchanging environments, lone actuating behaviours such as programmable deformation and locomotion are sometimes insufficient.…”

Editing the Shape Morphing of Monocomponent Natural Polysaccharide Hydrogel Films

“…This intriguing shape morphing results from the mismatch strain/stresses in local swelling behaviors which are determined by anisotropic tissue compositions and micro-/nanostructures within the organisms [3][4][5]. Inspired by these smart behaviors in nature, efforts have been focused on the development of artificial materials with programmable shape-morphing capabilities [6], such as electroactive polymers [7], liquid crystal elastomers [8], shape memory polymers [9], and stimuli-responsive hydrogels [10], which hold great promises to develop artificial muscles [11], reconfigurable tissue engineering scaffolds [12][13][14], and soft robotics [15][16][17] for a broad range of applications. Among these, hydrogels are one of the most attractive candidates, because they not only can swell and shrink in response to certain stimuli (thus changing their volumes reversibly) but also can exhibit unique superiorities in high similarity (water-rich structures and mechanical properties) to soft biological tissues, making hydrogels the most promising candidates in biomedical and robotic fields [18][19][20].…”