Epidermis-Like High Performance Wearable Strain Sensor for Full-Range Monitoring of the Human Activities

Stretchable strain sensors with outstanding performance are in critical demand with substantial progress in wearable electronic systems. In this work, a graphite conductive network-based active sensor material encapsulated within Ecoflex (sandwich structured Ecoflex/graphite/Ecoflex) is employed for strain and wearable monitoring applications. The typical active sensor material is successfully deposited onto the skin-like Ecoflex stretchable supporting material utilizing a spray coating technique to obtain a highly conductive brittle graphite nanoflake film. As a result, the Ecoflex/graphite/Ecoflex sandwich structured strain sensors exhibit high performance with a large strain sensitivity. Owing to the brittle-stretchable conductive network, the spray-coated strain sensor exhibited high gauge factors of 132 and 32 in the 0-20% and 20-40% strain ranges, respectively. Moreover, this strain sensor demonstrated a quick response speed (150 ms), prominent linearity (R-2 > 0.99 in the strain range of 5-20%), and high durability (>1000 stretch-release cycles at a large-scale strain of 30%) making it attractive for monitoring entire-range of human bodily motions including facial expressions (frowning, eye blinking, and cheek movement), vocal cord vibrations, and human articular joint motions (bending process of a finger, wrist, elbow, and knee ), thereby indicating enormous application prospects in healthcare devices, intelligent robotics, and human-computer interfaces.

Automated summary

This research presents a stretchable strain sensor using a graphite conductive network-based active sensor material encapsulated within Ecoflex. The sensor exhibits outstanding performance with high strain sensitivity and durability, making it suitable for monitoring various human bodily motions. It shows enormous application prospects in healthcare devices, intelligent robotics, and human-computer interfaces.