Silver nanowire networks embedded in urethane acrylate for flexible capacitive touch sensor

Flexible electrodes based on a percolated network of silver nanowires (AgNWs) and polymer are considered one of the best candidates for fabrication of flexible and even rollable touch sensors. A general approach to make the AgNW transparent electrode is based on an overcoating of AgNW dispersion onto a pre-formed transparent film. However, in that case, the nanowires could be easily detached from the film, because of the poor adhesion between them. Herein an inverted layer processing method has been employed to bury the AgNWs into the surface of a transparent polymer to enhance the adhesion. For this, a highly stiff and transparent polyurethane acrylate (PUA) was newly designed and synthesized by adding a cross-linker to the pre-polymer, with AgNWs patterned for a capacitive sensor then being successfully embedded in its surface to produce. By this unique structure with the PUA, highly transparent, conductive and mechanically more reliable capacitive touch sensor could be fabricated. The sensing capability and mechanical stability were confirmed by cyclic bend testing to a curvature radius of 0.5 mm.