Sodium Alginate-Based Frost-Resistant and Antidry Conductive Hydrogel for Human Motion Monitoring and Human–Computer Interaction

Wearable devices characterized by their flexibility are garnering significant interest, particularly in light of the emergence of notable conductive hydrogels. Although many of these hydrogels are highly conductive, they often lack adhesion. The ideal hydrogel should possess superior adhesive properties and a wide range of responsiveness. This study introduces a distinctive interpenetrating network conductive hydrogel, synthesized via a single-pot method employing lignosulfonate sodium and sodium alginate. The hydrogel's high mechanical strength (∼196 kPa modulus, ∼435 kPa tensile) and conductivity stem from its dynamic hydrogen bonds, electrostatic interactions, and 3D network. Furthermore, the hydrogel exhibits adhesive properties due to sulfonic, phenolic hydroxyl, carboxyl, and hydroxyl groups from lignosulfonate sodium and sodium alginate, enabling it to adhere to various material surfaces. It also detects human physiological signals with wireless monitoring capability, demonstrating a rapid response (∼100 ms) and high sensitivity, with a maximum gauge factor of 4 at strains of 0-10%.