Hofmeister Effect-Inspired Ti3C2Tx MXene-based Robust, Multifunctional Hydrogels

Developing multifunctional hydrogels with high strength, toughness, and conductivity is critical for various applications in soft robots, wearable devices, and human-computer interfaces. Inspired by the Hofmeister effect, a type of composite hydrogels was prepared using a freezing and salting-out approach, which combines transition metal carbide/nitride (MXene) and polyvinyl alcohol (PVA). The hydrogels exhibited great mechanical strength and toughness, and high conductivity, conferring its application as a multifunctional strain sensor. In addition, the synergy of highly conductive MXene, water-enriched porous structure, and sufficient MXene-PVA interfaces contributes to the controllable and high electromagnetic interference shielding effectiveness of 43-93 dB at thickness of 1.5-8.5 mm. Combined with the facile and scalable preparation approach for rational design of the MXene, PVA, water, and porous structure in the hydrogels, this work thus demonstrates the robust, ultra-flexible and electrically conductive multifunctional hydrogels for applications in Internet of Things, next-generation wearable electronics, electromagnetic protection, and smart devices.