A Strong and Double‐sided Self‐Adhesive Hydrogel Sensor

Abstract Flexible self‐adhesive hydrogel sensors are attracting considerable concerns in recent years. However, creating a self‐adhesive hydrogel sensor with excellent mechanical properties remains to be challenging. Herein, a double‐sided self‐adhesive hydrogel capable of strain sensor with high strength is demonstrated by penetration strategy. The middle poly(acrylic acid)‐polyacrylamide/Fe 3+ (PAA–PAM/Fe 3+ ) tough layer endows the double‐sided self‐adhesive hydrogel with high mechanical properties, while the bilateral poly[2‐(methacryloyloxy) ethyl]dimethyl‐(3‐sulfopropyl)ammonium hydroxide‐polyacrylamide (PSBMA–PAM) adhesive layers are used to ensure excellent adhesiveness on diverse substrates. The tough layer of the double‐sided self‐adhesive hydrogel sensor shows a strong interface bonding force against the adhesive layer. The double‐sided self‐adhesive hydrogel sensor enables excellent adhesiveness on diverse substrates. More importantly, it can accurately detect different strains and human motions as a self‐adhesive hydrogel strain sensor. This work manifests a new route of structural design to develop a self‐adhesive hydrogel sensor with excellent mechanical properties that is suitable for a wide range of applications.