The weaving art of mechanically and electronically robust hydrogel realizes multi-dimensional response of stretchable sensors

Abstract

In recent years, hydrogel-based soft electronics have been developed for the application of human motion, flexible robots and foldable displays. However, most existing conductive hydrogels have low toughness, single electron conduction or ionic conduction and poor adaptability towards complex applications. In this work, we obtained the toughness fiber-like hydrogel in three steps by doping nanofillers, directional extrusion freezing, and salting out. The proposed tough fiber-like hydrogel has a rich porous structure, which is achieved by doping the hydrophilic graphene nanosheets (HGNs) into a physically cross-linking polyvinyl alcohol (PVA) gel matrix. Directional extrusion freezing and salting out effect endow fiber-like hydrogel with better orientation ultimate nominal stress (∼9.5 MPa) and nominal strain (∼2200%). Meanwhile, the abundant porous structure facilitates ion migration and greatly enhances the ionic conductivity (up to 2.8 S m −1, at f = 1 MHz) of the hydrogel. The presence of HGNs endows the fiber-like hydrogel with excellent electronic conduction properties. Moreover, the weaving strategy is proposed to fabricate fiber-like hydrogel into hydrogel fabric film, which is effective for increased safety of stress-induced deformation and crack propagation. The woven hydrogel mesh bag can lift 6 kg of watermelon and the woven hydrogel net can bear a top-down weight impact of 1 kg. We also develop a novel type of woven hydrogel glove that can monitor complex hand movement. This work will provide new insight into the design of multifunctional materials with applications on electronic skin, wearable devices, and health monitoring.