Soybean protein-reinforced highly extensible and self-adhesive hydrogels with ultra-sensitive strain sensing for flexible electronic devices

Abstract

There is a growing interest in utilizing sustainable and renewable biomass resources to construct high-performance hydrogels for flexible electronics. In this study, soybean protein isolate (SPI) with abundant functional groups was introduced into the hydrogel matrix, while the connection between SPI, MXene and the polymer network was strengthened by hydrogen bonding. The sensible strategy overcame the problems of easy oxidation, agglomeration and weak interactions that existed in the binding of conductive filler MXene nanosheets with polymer chains. The prepared composite hydrogel exhibited integrated properties of high stretchability (>800 %), excellent self-adhesive property, plasticity, injectability, cyclic stability and durability in extreme environments (-20–60°C). Noteworthily, this hydrogel demonstrated high sensitivity and stable electrical resistance response to minor changes in tension, compression, bending, and temperature. In addition, this hydrogel exhibited excellent UV isolation and perspiration properties, making it ideal for practical applications of flexible devices in sports environments. The preparation of green, multipurpose, flexible electronics and human motion monitoring devices is made easier by the practical approach in this study.