Strain-resistance relationship in gold conductors for elastomeric-based flexible devices

Flexible electronic devices rely on effective conductors integrated with elastomeric substrates. This work reports on characterization of thin gold layers on flexible polymers as a platform for further research into their use in flexible electronic and microsystems. This work utilizes standard microfabrication techniques and a biocompatible, silicone polymer (polydimethylsiloxane) as the flexible substrate material. Flexible conductors defined by gold have been realized, and the dependence of resistance on geometry has been characterized. The results follow theoretical resistance dependence on geometry while showing an increase in the resistivity of the gold layer, a direct effect of deposition on elastomer causing wrinkles or striations in the metal layer. This work also discusses the effect of uniaxial mechanical deformation on thin film conductors and defines a procedure for creating and testing them in a repeatable manner. The ability to stretch the resistors by 10%, with full recovery to original resistance value is demonstrated. This work has implications for flexible device performance and provides a platform for integrated applications. Future work will explore combinations with piezoelectric thin films to enable conversion of mechanical to electrical energy, as this flexible platform will enhance the functionality of such energy generators.