High-Strength, Frost-Resistant PVA/PANI Conductive Hydrogels Suitable for Flexible Sensing

Conductive hydrogels show great potential for flexible sensors, yet their applications are limited by low strength, poor freeze resistance, and easy dehydration. To address these issues, this paper developed a multifunctional PVA (polyvinyl alcohol)/CMC (carboxymethyl cellulose sodium)/PANI (polyaniline)/PA (phytic acid)/BA (boric acid)/Fe 3+ hydrogel (denoted as PMNF) with a double-network structure formed via the Hofmeister effect and in situ polymerization. The hydrogel exhibits excellent mechanical properties (tensile strength: 236 kPa; elongation: 541%), high conductivity (2 S/m), and improved antifreezing behavior. At −12°C, it retains a conductivity of 0.86 S/m and over 300% elongation. It also demonstrates strong water retention after 15 days and stability in acidic/alkaline salt environments. Based on these properties, PMNF-based sensors reliably detect both subtle and large human motions under various conditions. This work offers a practical strategy for developing robust wearable electronics suited for real-world use.