EIS: A wearable device for epidermal pressure sensing

The development of epidermal electronics provides an enabling means for continuous monitoring of physiological signals and physical activities without affecting the quality of life. Such devices require high sensitivity for low-magnitude signal detection, noise reduction for motion artifacts, wearability for long-term comfort, and low-cost production for scalable manufacturing. However, the current epidermal pressure sensing devices, usually involving complex multilayer structures, have not fully addressed the aforementioned challenges. In this paper, we have presented a novel epidermal iontronic sensing (EIS) device, that is, a novel wearable pressure sensor with a single-sided configuration and reversible attachability to human skin. Notably, incorporating skin as part of the sensing architecture, the EIS devices offer an excellent pressure sensitivity (5 nF/kPa), an ultrafast mechanical response (in a sub-millisecond range), and a good long-term stability (>10,000) for both internal (body) and external (environment) mechanical stimuli. Demonstrations of its versatile application to wearable scenarios include measuring blood pressure pulsations, monitoring respiration rates, tracking muscle activities, and digitalizing hand palpation and gripping.