Self-Healing, Anti-Freezing Hydrogels and Its Application in Diversified Skin-Like Electronic Sensors

Abstract

Flexible, wearable and stretchable artificial electronic skin is essential for realizing applications in many fields such as remote medical monitoring, soft robotics, human health monitoring, and artificial intelligence. However, the key lies in the development of wearable electronic products with excellent stretchability, high sensitivity, good mechanical strength and multifunctional characteristics. In this work, an antifreeze conductive hydrogel sensor based on polyvinyl alcohol (PVA), silk fibroin (SF) and polypyrrole (PPy) is prepared. The hydrogel has good electrical conductivity, considerable stretchability (860%) and compressibility. It can achieve good self-healing performance under environmental conditions. Moreover, it could be accurately capture the changes for temperatu rerange of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$- 10^{\circ }\text{C}$ </tex-math></inline-formula> to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$50^{\circ }\text{C}$ </tex-math></inline-formula> , and could be further developed as a flexible temperature sensor. In addition, this work applies 3D printing method to prepare of wearable strain/pressure sensor. The resulting strain/pressure sensor has a wide sensing range (strain, 10%-706%; pressure, 0.5-124.75 kPa) and high sensitivity. The sensor is capable detect human movements, such as small finger movements and bending, pulse and so on. Due to the multifunctional properties and 3D printability of PVA/SF/PPy hydrogels, which is further reveals that hydrogels has fascinating potential applications in various fields such as human-machine interfaces, biosensors and wearable devices.