A low-hysteresis, self-adhesive and conductive PAA/PEDOT:PSS hydrogel enabled body-conformable electronics

Biomedical hydrogels always suffer from curvilinearity, deformability, and wetness associated with bio-tissues, which are therefore limited by low stability and longevity in practical applications. To overcome these issues, we have proposed a robust PAA/PEDOT conductive hydrogel and investigated its performance by using a low-crosslink-density polyacrylic acid (PAA) hydrogel with 82 wt% water. Meanwhile, poly(3,4-ethylenedioxythiophene):poly (styrene sulfonate) (PEDOT:PSS) has been used as both a major junction point and a conducting network contractor. Benefiting from the introduction of PEDOT:PSS, the resultant composite hydrogel exhibits strong adhesion (37.2 kPa), well-matched modulus with skin tissue (∼10 kPa), low swelling (2.88), and negligible hysteresis (η = 2.7% of 200% stretching, energy loss coefficient). As a scalable application platform, we have further demonstrated the potential application of this novel hydrogel as body-conformable electronics in a series of conceptual displays, including a full range of human motion responses, ECG signal detection, TENG device assembly, and energy harvesting application.