Preparation and Application of GaInSn/MXene Solid-Liquid Synergistic Reinforced PVA/Borax-Based Composite Hydrogel

Conductive hydrogels for flexible wearable sensors often suffer from a “force-electricity” trade-off caused by rigid fillers, along with the difficulty of fully restoring microscopic electrical pathways after damage. To address these challenges, a novel composite hydrogel with rapid mechano-electrical reconstruction and high sensing sensitivity was developed based on a “solid-liquid synergy” micro-network assembly strategy. Using polyvinyl alcohol (PVA) as the matrix and borax as a dynamic crosslinker, liquid metal (GaInSn) and two-dimensional MXene were incorporated via freeze–thaw cycles to fabricate a PVA-Borax-GaInSn-MXene hydrogel. The results demonstrate that the deformability of liquid metal and the rigid support of MXene synergistically toughen the polymer network, achieving a fracture stress of 205 kPa, elongation at break of 420%, and a high toughness of 430 kJ/m³. Electrical characterization shows a fast response time of 217 ms and excellent signal stability over nearly 500 deformation cycles. Furthermore, owing to the combined effects of microscopic physical interlocking and multilevel chemical bonding, the hydrogel exhibits strong adhesion to various substrates. Upon fracture, the damaged interfaces can autonomously reconnect at room temperature through dynamic borate ester bonds and a microscopic “liquid bridge” effect, enabling efficient simultaneous recovery of mechanical and electrical properties. This solid–liquid synergistic strategy effectively overcomes the low healing efficiency of conventional rigid conductive networks, offering a new material paradigm for the design of long-lifetime, high-fidelity flexible electronic devices.