Janus-type hydrophobic conductive ionogel with adjustable adhesion for amphibious strain sensing and triboelectric nanogenerators

To address the challenges of water absorption-induced swelling and poor underwater adhesion in conventional ionic conductive gels under humid conditions, this work developed a novel Janus-type conductive ionogel. The ionogel features a hydrophobic underwater adhesion layer (BO layer) synthesized via copolymerization of butyl acrylate and octadecyl acrylate, followed by in situ polymerization of a poly(butyl acrylate)/ N -hydroxyethyl acrylamide-based conductive ionogel layer (BHIG) atop the BO layer. The interpenetrating network structure between the BO and BHIG layers provides exceptional interfacial bonding strength, with a peeling force of up to 276.5 N m −1 . Moreover, the Janus ionogel also regulates the adhesion and environmental adaptability of the material. Specifically, the Janus ionogel exhibited switchable dual-to-single-sided adhesion under atmospheric conditions and single-sided instant adhesion in aqueous environments. Furthermore, the Janus ionogel demonstrates amphibious real-time strain sensing in both air and water. Leveraging its asymmetric structure, a Janus TENG (triboelectric nanogenerator) was fabricated without physical encapsulation, achieving efficient low-frequency energy harvesting in the environment.