Graphene Electronic Skin for Wearable Strain Sensing of Respiration and Finger Motion

Flexible and skin-conformal strain sensors are attractive for wearable health monitoring because they can follow body motion and capture subtle physiological signals with conformal contact to the skin. Graphene is a promising material for this application due to its exceptional thinness, flexibility, and compatibility with ultrathin epidermal platforms. In this work, we present a graphene-based electronic skin (e-skin) fabricated with stretchable interconnects on a spin-coated polyimide substrate. The strain response of the graphene e-skin is evaluated under repeated stretch/release cycles using a linearmotor-based setup, showing repeatable resistance variation with low drift and a gauge factor of 0.18. To demonstrate its application, the e-skin device was placed on the neck to monitor breathing (normal and abnormal) and swallowing, and on the finger to track motion. The sensor reliably captured distinct signal features from deep, normal, and rapid breathing, as well as apnea, choking, and asthma-like breathing mimics, along with swallowing and finger bending. Together, these results establish the proposed graphene e-skin as a simple, wearable platform for multimodal physiological and motion sensing.