Surface self-assembled PEDOT composite antifreeze hydrogel for flexible strain sensors and triboelectric nanogenerator

Conductive hydrogels have garnered substantial research attention owing to their exceptional flexibility, remarkable stretchability, and superior electrical conductivity. In this study, polyacrylamide/carboxymethyl cellulose sodium (PAM/CMC) double-network hydrogels were synthesized via a one-pot method, followed by in situ surface polymerization of the conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) on the hydrogel surface. Additionally, the freeze-resistance and moisture-retention properties of the hydrogel were enhanced through glycerol immersion, leading to the development of a PAM/CMC/PEDOT/Glycerol (MCPG) composite hydrogel with enhanced conductive performance. The MCPG composite conductive hydrogel exhibits outstanding mechanical properties, including an extraordinary tensile strain capacity (1750 %), excellent anti-freezing performance (maintaining flexibility at − 20 °C), and superior moisture retention capability. The strain sensor fabricated using MCPG hydrogel demonstrates an ultra-wide detection range (0–500 %), high sensitivity (GF = 5.65), and rapid response/recovery characteristics (300 ms), enabling comprehensive monitoring of various human joint movements. Furthermore, the triboelectric nanogenerator assembled with MCPG hydrogel (MCPG-TENG) exhibits exceptional electrical output performance, achieving an open-circuit voltage of approximately 118 V. This device is capable of powering small electronic devices and enabling information transmission. Consequently, the high-performance flexible sensors and TENGs developed in this study, based on the self-assembly of PEDOT on the hydrogel surface and leveraging their superior stretchability and stable conductive properties, hold broad application potential in the fields of intelligent human–machine interfaces and wearable electronic devices.