Solution-processed deposition based on plant polyphenol for silver conductive coating and its application on human motions detecting sensor

Abstract A highly conductive environmental benign strategy for even coating of metal ion is of the great demand for various applications. This article proposes a nature originated polyphenol-Tannic acid (TA) based method for uniform coating of silver (Ag) on the surface of polyurethane (PU) sponge for synthesizing conductive composite. Solution-processed layer-by-layer (LbL) coating technique has been developed for fabricating Ag coated PU sponge that is performed at room temperature, avoiding the requirement of harsh and unstable conditions. The developed Ag nanocoated PU sponges are then successfully utilized to serve as a compressive strain sensor. The sensor offered the good performances under repeated cycles of compression, a significant change in the resistivity has been observed under various applied loads. The flexibility and sensitivity are further exploited and showed resistance signals upon certain human motions including bending of a finger, wrist, elbow, knee, throat, foot movements and speech recognition. The TA based LbL deposition of Ag in this paper could be generalized through depositing Ag nanocoating on diverse natural and synthetic substrates including paper, fabric, and latex. The developed process has a promising way for simple, facile, and eco-friendly synthesis of the conductive substrates and offers potential for scale-up production.