High-conductivity PBFDO-based self-adhesive hydrogel for low-hysteresis flexible sensing applications

Abstract

Conductive hydrogels have emerged as key materials in the field of flexible electronics due to their excellent electrical conductivity and flexibility. Addressing the issues of low electrical conductivity and water-phase incompatibility associated with traditional conductive polymer fillers, this study innovatively developed an n-type high-conductivity polymer poly(benzodifurandione) (PBFDO), which combines ultra-high intrinsic conductivity with exceptional water-phase miscibility. The PAM-PBFDO hydrogel exhibited significantly enhanced conductivity of 43.86 mS m⁻¹, representing a 4.7-fold improvement over pure polyacrylamide (PAM) hydrogel. Additionally, PBFDO's ester carbonyl groups established robust hydrogen bonds with PAM's amide groups, enhancing mechanical strength. Simultaneously, its rigid benzene rings served as physical crosslinks, preventing chain slippage while boosting fatigue resistance and durability. The resulting PAM-PBFDO hydrogel demonstrated remarkable properties, including strong self-adhesion (179 kPa), ultra-low mechanical hysteresis (∼5.6 %), high sensitivity (4.38–33.96), and fast response time (∼40 ms). As a flexible strain sensor, the PAM-PBFDO hydrogel shows great potential in various applications such as human motion monitoring, smart home pressure sensing, and industrial environment monitoring.