A Multifunctional, Antifreezing, and 3D-Printable Conductive Hydrogel Enabled by a Phytic Acid-Based Synergistic Strategy for Wearable Strain Sensing

Inspired by biological tissues, this study presents a “multidimensional network synergistic enhancement” strategy to fabricate a high-performance composite hydrogel (PSPC) via a one-pot, physically cross-linked method. The material integrates a polyvinyl alcohol (PVA) and sodium alginate (SA) dual network, reinforced by cellulose nanofibers (CNF), Mg 2+ ions, and a multifunctional phytic acid (PA) phase. This synergistic design imparts remarkable mechanical properties, including high tensile strength (2.6 MPa) and toughness (4.6 MJ/m 3 ), alongside exceptional anti-swelling (105%) and anti-freezing (−29°C) capabilities. The inclusion of PA also affords high ionic conductivity (7.8 mS/cm), enabling the 3D printing of flexible sensors with high sensitivity (1% strain) and rapid response (400 ms) for physiological monitoring. This entirely physically cross-linked hydrogel is also fully recyclable, offering a sustainable and novel material concept for advanced, customizable wearable devices. Highlights One-pot prepared PSPC hydrogel with multidimensional network via synergistic reinforcement. PSPC hydrogel shows high mechanical and excellent anti-swelling performance. PA enables anti-freezing and high conductivity without weakening mechanics. PSPC sensor has high sensitivity and fast response for human motion detection. Printable and recyclable PSPC hydrogel for customizable 3D sensors.