Fast-Recoverable, Self-Healable, and Adhesive Nanocomposite Hydrogel Consisting of Hybrid Nanoparticles for Ultrasensitive Strain and Pressure Sensing

To meet various practical requirements and enhance human experience, hydrogels possessing multifunctionality are of great significance for flexible wearable sensors. Herein, a novel strategy has been developed to fabricate nanocomposite hydrogels with a combination of excellent stretchability, rapid recoverability, self-healing, and outstanding adhesiveness. The PAAc/SiO2-g-PAAm nanocomposite hydrogels were facilely prepared through the polymerization of acrylic acid (AAc) using SiO2-g-polyacrylamide core–shell hybrid nanoparticles (SiO2-g-PAAm) as the dynamic cross-linking center. The densely dynamic hydrogen bonds between PAAc matrices and grafted PAAm chains could reversibly be destructed and reconstructed to dissipate a large amount of energy. Due to this unique feature, the formulated hydrogels showed a wide spectrum of desirable properties, including skin-mimetic modulus, excellent stretchability (1600%), exceptional self-healing properties (96.5% at ambient temperature), and fast recoverability. The sensors fabricated with the prepared hydrogels exhibited a high detection sensitivity in the strain range from 50% to 500% with a gauge factor value of 5.86, rapid response time, and good antifatigue performance. Depending on the outstanding adhesiveness, this sensor could attach to different substrates to release the real-time motion monitoring. In the practical wearable sensing test, various human motions, including tiny-scaled swallowing, laughing, and speaking, as well as large-scaled wrist, elbow, and knee movements during basketball shooting, could be sensed. These demonstrations heralded the potential application of our sensor in accurate and long-term human motion monitoring.