Ying-Hung Chen, Ping-Yen Hsieh, Yu-Te Liu, Yueh-Lin Hung, Yu-Wen Chen, Ju-Liang He, Feng Chia University, Taiwan
Physiological monitoring technologies are increasingly important in confronting the challenge of increasing aging population and raising healthcare costs. Epidermal electronics (EE) for physiological monitoring holds significant promise due to its ease for data collection. Thin-film strain gauge, as the core of EE, can be attached directly onto the skin to detect subtle strain caused by heartbeat, breathing, brain wave and other vital physiological information. Current existing strain gauge falls into a limited reliability and lifespan due mainly to the poor adhesion between the conductive electrode and the substrate, as well as unnecessary film thickness to decrease sensitivity. This study aims to overcome these shortages by using high-power impulse magnetron sputter deposition (HiPIMS). HiPIMS offers high-density plasma while maintaining low deposition temperatures (<100°C), making it ideal for creating strongly adhered and strain-resistant conducting electrodes. HiPIMS deposited metal films (silver, gold, copper, and brass) serves to perform as the conducting electrodes on polymeric substrates with stretchability and low electrical resistance are revealed in this study. Static tensile test and dynamic reliability test were evaluated to reveal their suitability for EE applications.