Flexible and highly conductive Ag/G-coated cotton fabric based on graphene dipping and silver magnetron sputtering

Flexible electronic devices have attracted considerable attention in recent years. Textile fabrics have been widely used to fabricate flexible strain sensors owing to their high flexibility. However, the ordinary textile fabric is electrically insulating, which limits their sensitivity to strain. In this article, cotton fabric endowed with high electrical conductivity was prepared by a two-step process of dipping and coating. It was firstly modified with a continuous reduced graphene oxide thin film by using a dipping method and then coated with silver (Ag) thin films by using a magnetron sputtering system. In addition, a strain sensor was also fabricated using the resultant fabric, namely the silver/graphene cotton (Ag/G-coated cotton). Our results revealed that the Ag/G-coated cotton fabric sputtered at 200 W for 25 min has the highest electrical conductivity and its average surface resistance is 2.71 Omega/sq. Moreover, the fabricated strain sensor based on Ag/G-coated cotton fabric exhibited the advantages of high sensitivity, large workable strain range (0-20%), fast response and great stability. What's more, real-time monitoring of human motions, such as flexing and finger rotation, could be achieved by the sensor. Overall, the effective flexibility and high electrical conductivity of the Ag/G-coated cotton fabric have been validated effectively and make it one of the promising candidates for its applications in wearable electronic devices.