Controllable Shape Morphing Nanocomposite Hydrogels for Robust Multi-Stimuli-Responsive Actuators

Abstract

Amazing anisotropic hydrogel actuators with outstanding mechanical properties, multistimuli-responsive properties, and diverse architectures have been simply achieved by hydrogen bonding-directed assembly of two or more homogeneous nanocomposite (NC) hydrogel blocks. The NC hydrogels using clay nanosheets as the efficient cross-linker become strong enough to bear high levels of elongation and compression and exhibit a sensitive near-infrared (NIR) light response with the matrix embedding of graphene oxide (GO) nanosheets or ferroferric oxide (Fe 3 O 4 ) nanoparticles, as well as a magnetism response with embedded Fe 3 O 4 nanoparticles. Those homogeneous NC hydrogels with tunable composition, tailorable shape, and controllable state offer a versatile toolbox and complex shape deformation capacity for the anisotropic actuators. We demonstrate the reliability and practicability of our approach for fabricating various actuators including crawler, circuit switch, and targeted cargo-delivery vehicle, attributing to the rapid, reversible, and repeatable temperature/NIR light-triggered shape morphing. Overall, this work provides a facile and universal strategy for developing the application of the homogeneous NC hydrogels to construct robust multiresponsive actuators with sophisticated structures as well as controllable shape deformation behaviors.