Zwitterionic Hydrogel Electrolyte with Tunable Mechanical and Electrochemical Properties for a Wearable Motion and Thermal Sensor

A high-performance zwitterionic hydrogel electrolyte was successfully fabricated, in which the polymer chains were cross-linked by multiple reversible non-covalent bonds. The mechanical and electrochemical properties of the synthesized zwitterionic hydrogel electrolyte can be facilely modulated by immersing the as-prepared zwitterionic hydrogel in saline solutions with different concentrations. The processed zwitterionic hydrogel electrolyte exhibits tunable mechanical and electrochemical properties (favorable elasticity of 3.2-202 kPa, high fracture energy of 0.34-1.15 MJ m-3, high stretchability of 1000-2880%, high self-healing efficiency of 30-70%, and coordinated ionic conductivity of 0.16-1.65 S m-1) to satisfy the needs of different application scenarios. A wearable sensor based on the zwitterionic hydrogel electrolyte is demonstrated. The wearable sensor can be attached to a part of the human body, and various human motions can be successfully monitored. Besides being functionalized as a motion monitor, the wearable sensor can also be used as a thermometer to monitor the body temperature instantaneously, showing an encouraging and strong practicability in wearable electronic device.