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

Abstract

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.