Flexible Multimodal Sensor Based on Double-network Hydrogel for Human and Robotic Applications

With the development of wearable technology, there are higher requirements for wearable sensors, such as multimodal sensing, superior mechanical properties, and simple and easy-to-fabricate structures. However, it is difficult for existing flexible sensors to possess all these advantages simultaneously. Herein, a flexible multimodal sensor based on sodium alginate/polyvinyl alcohol/graphene oxide double-network hydrogel was prepared. The multiple hydrogen bonds between the two networks provided the gel with great mechanical properties. In addition, the flexibility and easy-to-fabricate simple structure of hydrogels were ideal for wearable sensors. In particular, the hydrogel sensors have a temperature sensitivity of up to 2.81 %/degrees C between -20 degrees C and 55 degrees C and pressure sensitivity of 0.03 kPa(-1), both of which have excellent properties of stability and repeatability. Besides, the sensor also presented a humidity sensitivity of 0.027 % RH-1. This work also applied hydrogel sensors to practical applications and provided a new idea for wearable technology.