Characteristics of polyurethane nanowebs treated with silver nanowire solutions as strain sensors

This study presents a simple methodology to fabricate a conductive polyurethane nanoweb for use as a textile strain sensor. The purpose of this paper is to (1) fabricate an electrically-conductive polyurethane nanoweb coated with silver nanowires and investigate changes in its electrical resistance in relation to the amount of silver nanowires, (2) investigate changes in the electrical resistance of the polyurethane nanowebs under stretching, (3) evaluate the mechanical and chemical properties of the treated nanowebs, and (4) observe the breathability of the coated nanowebs. Silver nanowires dispersed in ethanol (AgNW) were diluted as necessary by addition of ethanol. Electrical conductivity was imparted to the polyurethane nanowebs by a pour-coating process utilizing AgNWs. The initial electrical resistance of the specimens and the changes with stretching up to 20% and release were recorded, and the data were analyzed. The electrical resistance decreased in accordance with the AgNW concentration. The electrical resistance increased under stretch and decreased upon release. Field-emission scanning electron microscopy with energy dispersive spectroscopy and atomic force microscopy analysis displayed the polyurethane, the silver nanowire attachment to the fibers, and the silver nanowire networks. According to Fourier transform infrared spectroscopy analysis, hydrogen bonds derived from the treatment with ethanol generated a crimp structure on the polyurethane nanowebs. Both tensile strength and bending rigidity increased after the treatment. Breathability tests showed that the specimens had semi-windproof and good water vapor transmission properties as textiles.