Zwitterionic Poly(sulfobetaine methacrylate) as a Building Block to Construct a Highly Stretchable, Mechanically Tough, and Antifreezing Conductive Hydrogel for Wearable Strain Sensor and Triboelectric Nanogenerator

Flexible conductive hydrogels hold significant potential in wearable electronics. However, they suffer from poor conductivity and inadequate mechanical properties. Herein, we proposed a borax-connective poly(vinyl alcohol) (PVA)/poly(acrylic acid- co -[2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide) P(AA- co -DMAPS) double network hydrogel (PVA-AA-DMAPS), in which a zwitterionic monomer (DMAPS) was introduced to build a unique double network and boost the conductivity and mechanical properties. The obtained hydrogel not only achieved splendid mechanical properties (stress: 913.0 kPa, strain: 1242.3%, and toughness up to 5.38 MJ/m 3 ) and ionic conductivity (1.64 S/m) in the presence of DMAPS but also exhibited antifreezing performance. Further, the PVA-AA-DMAPS hydrogel was employed to construct a highly sensitive strain sensor (gauge factor, GF max = 2.95) and TENG with an excellent electrical output performance. At −20 °C, the TENG showed a high open-circuit voltage (183.7 V), which effectively distinguished subtle human activities, transmitted information, and powered a commercial calculator. Therefore, the developed poly(sulfobetaine methacrylate)-based hydrogel is expected to hold significant promise for human healthcare monitoring and energy supply applications.