High-Strength Conductive Hydrogels Reinforced by Tannic Acid-Modified Silk Nanofibers for Wearable Strain Sensors

Conductive hydrogels show promise for flexible wearable sensors but face challenges such as low mechanical strength, fragility, poor stability, and insufficient sensitivity. In this study, a high-strength, highly sensitive, and stable composite hydrogel has been synthesized by a one-pot method. The incorporation of tannic acid-modified silk nanofiber (ST) composites and Ti₃C₂T_x nanosheets (MXene) significantly enhances the mechanical performance of the poly(vinyl alcohol) (PVA) hydrogel, endowing it with notable antibacterial and conductive properties. The PVA/MXene/ST conductive hydrogel with an optimal composite ratio achieves a tensile breaking strength of 0.74 MPa, an elongation at break of 506%, and a 7.6-fold increase in compressive strength compared to the pure PVA hydrogel. The hydrogel-based flexible sensors demonstrate dual-mode sensing capabilities (stretching and compression) with stable and sensitive performance over 500 cycles. Moreover, the hydrogel exhibits good antibacterial properties, antifreezing capability (−20 °C), and water retention capability.