Composites of Poly(dimethylsiloxane) and Silica Nanoparticles as an Approach to Manipulating the Conductivity of Stretchable Gold Films
Stretchable conductors play a fundamental role in wearable electronics as device electrodes and interconnects. Polydimethylsiloxane (PDMS) is conventionally used as the platform for stretchable conductors which are fabricated by depositing a thin layer of gold metal onto the surface. These gold films fail electrically under minimal strains (15-20% linear elongation) due to uncontrolled crack propagation through the metal film. Adding a rough microstructured polymer layer onto the PDMS surface preserves electrical conductivity in metal films to higher elongations of 60% due to the numerous sites for strain localization. However, such heterogeneous layered systems are vulnerable to delamination, leading to device failure. In this thesis, we fabricate a composite layer by combining silane modified silica nanoparticles together with PDMS prepolymer on top of an elastomeric substrate to enable the fabrication of stretchable gold films.