Integrated Flexible Supercapacitors Fabricated by Biocompatible Self‑Adhesive Polyacrylamide/Chitosan...

A self‑adhesive supercapacitor is developed based on a biocompatible hydrogel matrix integrated with poly(3, 4‑ethylenedioxythiophene): poly(styrene sulfonate) as the conductive material. For biomedical devices, achieving stable adhesion to dynamic biological tissues is a key challenge. To address this, an integrated structure is created through the in situ polymerization of poly (3, 4‑ethylenedioxythiophene): poly(styrene sulfonate) on a hydrogel composite composed of polyacrylamide, polydopamine, and quaternary ammonium salt of chitosan. This method eliminates interfacial resistance and enhances mechanical stability. The hydrogel matrix is optimized with 20% acrylamide, and the conductive polymer is polymerized for 36 h, yielding a specific capacitance of 0.67 mF·cm^-2 at 0.03 mA·cm^-2. The device exhibits strong tissue adhesion with an interfacial toughness of 0.20 kJ·m^-2 and a shear strength of 1.5 kPa, resulting from hydrogen bonding, π-π stacking, and electrostatic interactions. A hemolysis rate of 0.35% confirms biocompatibility, while antibacterial properties are provided by the quaternary ammonium salt of chitosan. This work provides a strategy for developing adhesive and biocompatible energy storage components toward future bio‑integrated electronics.