Super-stretchable, elastic and recoverable ionic conductive hydrogel for wireless wearable, stretchable sensor

Due to their outstanding flexibility and high sensitivity, stretchable ionic conductive hydrogel-based sensors are considered one of the best candidates for the real-time monitoring of human body motion as a wearable health-care detection electronic device. In the detection of body motion, the ionic conductive hydrogel is sensitive to its deformation. However, the current reported hydrogels struggle to recover their initial shape after numerous repeated stretching cycles owing to fatigue, leading to their response insensitivity and service life degradation. In this work, a super-stretchable and recoverable ionic conductive hydrogel (double network polymer hydrogel (SA-Zn): ZnSO4/sodium alginate/poly acrylic-acrylamide) was designed as a stretchable sensor for human body motion detection. The SA-Zn hydrogel exhibited outstanding stretchability (up to 4000% tensile strain) and excellent shape self-recovery ability (20 min recovery time). After self-recovery for 50 cycles, the hydrogel still retained good flexibility, stable self-recovery ability and high conductivity. More importantly, the assembled wireless wearable stretchable sensor (SA-Zn-W) could transform human body motion into a visual electrical signal when combined with a Wi-Fi transmitter, revealing its excellent sensitivity, fast response, effective identification and stable electromechanical repeatability. The superior performance of the SA-Zn-W offers a promising solution for effectively and remotely detecting human body motion.