Integrally formed Janus adhesive conductive hydrogel with excellent interfacial stability and fatigue resistance for robust flexible sensing

<h2>Summary</h2> Engineering Janus conductive hydrogel sensors with asymmetrically adhesive characteristics remains challenging due to complicated fabrication procedures, unstable interfacial connections, and fatigue-induced deterioration. Herein, a one-step integrated strategy is proposed that combines Pickering emulsion-enabled phase separation with charge shielding to construct Janus adhesive conductive hydrogel sensors, featuring a tri-layer architecture with contrasting stiffness: a soft adhesive top layer for skin-adaptive attachment, a stiff anti-adhesive bottom layer providing mechanical and electrical support, and a gradient middle layer bridging the two distinct layers. This tri-layer structure significantly achieves asymmetric adhesion diversity (15.7-fold) while maintaining symmetric wettability on opposite surfaces. It also enhances interfacial mechanics, demonstrating an interfacial strength of 24.31 kPa over 300 cycles, thereby outperforming conventional strategies (8.62 kPa; 60 cycles). Consequently, the assembled hydrogel sensor effectively prevents unintentional adhesion to external objects and supports robust, long-term dynamic motion detection and pressure perception, offering promising potential for flexible sensing applications.