Self-Connected Ag Nanoporous Sponge Embedded in Sputtered Polytetrafluoroethylene for Highly Stretchable and Semi-Transparent Electrodes

High-performance wearable electronics require highly stretchable and conductive materials that are prepared by simple, scalable processes to be implemented in the essential roles of electrodes and interconnects. Here, room temperature fabrication of highly stretchable electrodes consisting of self-connected Ag nanoporous sponge embedded in polytetrafluoroethylene (PTFE) matrix on stretchable polyurethane substrates using a metal-polymer co-sputtering process is demonstrated. The metallic Ag nanoporous sponge networks (NSNs) embedded in PTFE matrix show minimal changes to resistance even after stretching by 50% and after 10 000 cycles under 20% strain due to the well-connected Ag NSNs and the stretchable PTFE matrix. The feasibility of this hybrid material as stretchable interconnects and electrodes for stretchable thin film heaters and strain sensors is also demonstrated. Because the Ag NSNs embedded in PTFE matrix are simply fabricated by a typical sputtering process, which is compatible with current electronics fabrication processes, it is strongly expected that the Ag-PTFE hybrid electrodes can be easily applied as universal stretchable electrodes for wearable thin film heaters, stretchable interconnectors, and stretchable strain sensors.