Multi-Crosslinked Hydrogel-Based Needle Structure Capacitance Sensor with High Sensitivity and Stability

The hydrogel-based sensor has better elasticity than the existing elastomer sensor, so the distance between the two electrodes can be reduced. Also, since the amount of change in contact area is also large, the amount of change in capacitance is excellent. Especially, by adopting a micro needle structure that can maximize the change in contact area, the change in capacitance is increased. However, the previous hydrogel-based sensor lacks recipe research to create a structure, and adding a structure reduces stability and repeatability, limiting its application as a sensor. In this paper, poly(acrylamide-co-N, N′-methylenebisacrylamide) multifunctional hydrogel can overcome the aforementioned limitations. Then, by making a hydrogel-based sensor with a micro needle structure, high sensitivity is sought by adjusting the amount of N, N′-methylenebisacrylamide. In addition, by adding sodium dodecylbenzenesulfonate lauryl acrylate, the stability of the structure that does not interfere with sensitivity is increased. This hydrogel-based sensor is a human-friendly material that can be applied not only to the biomedical measurement field, but also to fields where existing elastomer sensors are applied, such as robots, hydraulic pressure measurement, and aviation.