Interface-engineered Ionically Conductive Polyoxometalate-based Hydrogels with High Stretchability and Notch-insensitivity for Wearable Sensors

The rapid advancement of wearable sensors necessitates ionically conductive hydrogels that simultaneously exhibit high stretchability, damage tolerance, and reliable adhesion. However, achieving these properties in a single material remains a significant challenge. Herein, we report an ionically conductive polyoxometalate (POM)-based hydrogel (PAA/L-arg@SIW) fabricated by incorporating L-arginine (L-arg)-modified silicotungstic acid nanocomplexes (L-arg@SIW) into a poly(acrylic acid) (PAA) network as a multifunctional dynamic crosslinker. Strong electrostatic interactions and hydrogen bonding between rigid L-arg@SIW nanoclusters and flexible PAA chains generate a three-dimensional hard-soft synergistic network, in which dynamic crosslinks preferentially rupture and re-form under mechanical loading, thereby dissipating energy and suppressing crack propagation. Consequently, the hydrogel exhibits exceptional stretchability (fracture strain >1500%), high toughness (1483 kJ/m 3 ), outstanding crack resistance (fracture energy up to 6.82 kJ/m 2 ), and high ionic conductivity (0.15 S/m), along with robust adhesion to diverse substrates. Hydrogel-based sensors demonstrate high strain sensitivity (gauge factor (GF)=8.06), fast response, and excellent cyclic stability, enabling reliable monitoring of human motion and high-fidelity acquisition of electrocardiogram (ECG) and electromyogram (EMG) signals. This study presents an effective strategy for constructing high-performance ionically conductive hydrogels for wearable sensing applications. The alternative text for this image may have been generated using AI.