Bioinspired Shape Memory Hydrogel Artificial Muscles Driven by Solvents

Abstract

Although hydrogels containing large amounts of water are similar to natural muscles, they are a challenge to be used in artificial muscles because of their poor mechanical properties and low work capacities. The current paper describes the design and fabrication of tendril-inspired hydrogel artificial muscles via a consecutive shaping process. Tunicate cellulose nanocrystals (TCNCs) are incorporated into polymeric networks via host−guest interactions to reinforce the hydrogel. Tendril-inspired hydrogels are obtained by treating the TCNC-reinforced hydrogels with a consecutive stretching, twisting, and coiling process and locking the shaped structure through Fe 3+ /−COO − ionic coordination. These hydrogel muscles exhibit a high actuation rate, large actuation strain, and shape memory property in response to solvents. The actuation performances of hydrogel muscles are affected by their chirality, twist density, applied stress, and temporary shape. Moreover, a homochiral hydrogel muscle with temporary shape II shows comparable contractile work capacity with a natural muscle, which can be applied as the engine to actuate the movement of a car model. This work demonstrates a simple and effective strategy for the fabrication of hydrogel artificial muscles that have great potential for biomedical application as a result of their comparable water content and contractile work capacity with natural muscles.

Recent Advances in Host‐Guest Supramolecular Hydrogels for Biomedical Applications

“…In another example, a novel photo-adaptable shape memory hydrogel was developed by Zhao and colleagues in 2019 using two reversible supramolecular interactions. [100] The hydrogel was constructed by host-guest assembly based on α-CD and [98,99] Copyright 2018, Elsevier Ltd. Copyright 2021, American Chemical Society.…”

A Shift from Efficiency to Adaptability: Recent Progress in Biomimetic Interactive Soft Robotics in Wet Environments

“…[90] Copyright 2018, Springer Nature. HA <87 [ 84,92] 10 −2 [ 83] -10 2 [ 93] 10 −3 -0.1 [94] 10 −5 [ 95] -35 [96] -<1 [97] Light, heat, pH, water, etc. TCY 0.2-90 [98][99][100][101][102][103] 2.5 × 10 3 [ 104] -1.6 × 10 4 [ 105] 2.4 × 10 3 [ 91] 1.3 × 10 3 [ 105]− 5 × 10 3 [ 104] 15 [98] -50 [ 103] 2-12 [ 79,99,100,106] Heat, solvent Reproduced with permission.…”

Multi-level encryption of information in morphing hydrogels with patterned fluorescence

“…Many hydrogels are responsive to external stimuli, 24–26 which are widely used to devise morphing structures 27–30 and in soft actuators 31–35 and soft robots. 36–39 Such shape-changing ability of hydrogels has been harnessed to enhance information security in recent years, which can upgrade the encryption level of information in terms of morphing structures.…”