Adhesive and Conductive Hydrogel Fabricated via Self-Assembly of Folate Compounds Driven by π–π Stacking and Hydrogen Bonding

Adhesive and conductive hydrogels, as water-rich functional materials, exhibit exceptional promise in biomedicine and motion sensing. Developing a natural and convenient fabrication method for constructing multifunctional hydrogels with these capabilities remains highly desirable. Herein, we present a highly stretchable, soft, and adhesive conductive hydrogel-based electronic skin for real-time human activity monitoring and biophysical signal transduction. The material is fabricated by integrating folate (FA) as sacrificial dissipation centers into PAM-co-PDEA (poly(acrylamide-co-2-(dimethylamino) ethyl methacrylate)) copolymer backbones. Systematic characterizations (1H NMR, XRD, SEM, and Molecular Dynamics simulations) elucidate that hydrogen bonding and π–π stacking govern the self-assembly of FA moieties into clusters. Consequently, the hydrogel exhibits an exceptional elongation rate (λ = 1380%), along with softness and interfacial adhesion (30 J/m2). Furthermore, the dynamic ion-pair interactions between FA clusters and polymer chains establish efficient charge transport pathways, achieving remarkable conductivity (0.62 S/m) and strain-sensitive responses. The resultant PAM-co-PDEA@FA hydrogel demonstrates excellent wearability and flexibility, enabling its application in wearable motion sensors and ECG (electrocardiogram) electrodes. This work provides a green and scalable synthesis strategy that endows the hydrogel with adhesive and conductive properties, thereby promoting the rapid development of gel-based e-skins and sensors.