Preparation And Properties Of Graphene Reinforced Conductive Casein Hydrogel

As a kind of attractive soft material,hydrogel has three dimensional network structure and adjustable physical and chemical properties.In recent years,conductive hydrogels have been widely used in flexible sensing fields,such as supercapacitors,sensors,touch screens and electronic skin,due to their excellent flexibility,good electrical properties and adjustable mechanical properties.In order to obtain conductive hydrogels with better performance,a variety of synthetic strategies have been developed,such as adding ions or electronconducting materials to the hydrogels,which provide a broad application prospect for the development of flexible electronic devices.In recent years,hydrogel-based flexible wearable sensor has attracted extensive attention,which could be used as a wearable intelligent health monitoring system to track the physiological signals of human body in real time.At present,the hydrogel sensor has the defects of low sensitivity,slow response speed and inability to adhere seamlessly to the skin.So,the preparation of flexible hydrogel sensors with fast response speed,high sensitivity and strong self-adhesion is a great challenge.Therefore,in this paper,sodium caseinate(SC)and reduced graphene oxide(r GO)were introduced into polyacrylamide(PAAm)hydrogel system for obtaining the SC/r GO/PAAm hydrogel-based wearable strain sensor with high sensitivity,fast response,wide monitoring range and strong self-adhesion by the way of synergistic conduction of ions and electrons.The introduction of casein could not only give good adhesion to hydrogels,but also provides a good ion conduction pathway.In addition,the introduction of r GO provided an electron conduction pathway while enhancing the mechanical strength of hydrogels.The synergistic conductive mode of electron and ion made the hydrogel exhibited rapid responsiveness(190ms),high sensitivity(GF=13.14)and wide strain monitoring range(0.1-1100%).Thus,SC/r GO/PAAm hydrogels could be used to detect small signal changes(such as speaking)as well as large-scale human movements(such as bending knees).The synergistic conduction of ion and electron provides a reference for the preparation of highly.