Ion beam-induced enhancement of stretchability and flexibility in conductive AgPdCu-polytetrafluoroethylene composite electrodes for wearable strain sensors

We prepared homogeneously mixed APC-PTFE composite films with a sheet resistance of 0.97 Ohm/sq at room temperature by co-sputtering AgPdCu (APC) and polytetrafluoroethylene (PTFE) targets simultaneously. Oxygen ion beam treatment (IBT) significantly enhanced the adhesion and mechanical flexibility of the APC-PTFE composite electrode by improving its surface morphology, as confirmed by X-ray photoelectron spectroscopy and atomic force microscopy analysis. The APC-PTFE composite electrode exhibited minimal resistance changes of 0.44 %, 1.79 %, and 1.88 % under repeated bending, folding, and rolling tests, respectively. Furthermore, the optimized APC-PTFE composite electrodes showed a much lower resistance change than the bare APC electrodes during stretching, demonstrating superior stretchability. Using the optimized APC-PTFE composite electrode, we fabricated wearable strain sensors for wireless motion sensing. These sensors exhibited an extended sensing range and stable performance. The effective motion sensing capabilities of the APC-PTFE-based strain sensor suggest that the APC-PTFE composite electrode prepared using IBT is a promising stretching electrode for wearable and flexible electronics.