Design and evaluation of a highly stretchable and conductive thin film for tactile sensors

Keeping good conductivity at high stretching strain is one of the main requirements for the design of flexible electronic devices. The elastic nature of siloxane-based elastomers enables many innovative designs in wearable sensor devices and non-invasive insert instruments. Over the last few years, Poly-di-methyl-siloxane (PDMS) thin films have been heavily used as the substrates in the fabrication of tactile sensing devices due to their high sensitivity, good elasticity and outstanding biocompatibility. However, these kinds of conductors usually suffer poor tearing property and insufficient compliance to curved surfaces, which greatly limited their applications. Currently no three-dimensionally mountable sensor arrays have been reported. In this work, we developed an excellent mechanically compliant skin-like conductors by patterning silver nano wire traces in Dragon Skin^® substrate instead of PDMS substrate, high cross-link quality was achieved then. Moreover, to further enhance the conductivity, a thin gold layer was coated on the AgNWs strips, 4 different fabrication routines was designed and conducted. Thanks to the intrinsically outstanding physical property of Dragon Skin and the uniform embedment built in fabrication process, the AgNWs/Dragon Skin layer showed convincible advantage over AgNWs/PDMS layer both in mechanical capability and conductive stability.