Thin Gold Film Deposited on PDMS for Stretchable Electrical Interconnections and Bio-compatible Applications via Textured 3D Printed Mold

This study demonstrates that 3D printing significantly enhances the surface roughness of PDMS substrates, leading to a substantial increase in the maximum allowable elongation before a drastic rise in electrical resistance. The PDMS substrates were molded using 3D-printed molds with varying surface treatments to achieve different roughness levels. The untreated samples displayed higher surface roughness, allowing for elongation up to 12.5% before the electrical resistance increased sharply due to the formation of micro-cracks in the gold film. Conversely, smoother surfaces, achieved through ethanol mist treatment, showed higher initial resistance and reduced elongation capacity. This finding underscores the critical role of substrate roughness in stretchable electronics, where optimizing surface characteristics is essential for balancing adhesion and mechanical robustness, thus improving the performance and reliability of bio-compatible and stretchable electrical interconnections.