Auxetic Foam‐Based Contact‐Mode Triboelectric Nanogenerator with Highly Sensitive Self‐Powered Strain Sensing Capabilities to Monitor Human Body Movement

TLDR

The sensor is built from auxetic polyurethane foam, conductive fabric, and PTFE, where stretching the foam expands it into the PTFE, generating contact electrification. The resulting device exhibits the highest sensitivity among triboelectric nanogenerator strain sensors, enabling effective monitoring of human body movement, weight measurement, and vehicle seat belt motion.

Abstract

The first contact‐mode triboelectric self‐powered strain sensor using an auxetic polyurethane foam, conductive fabric, and polytetrafluroethylene (PTFE) is fabricated. Utilizing the auxetic properties of the polyurethane foam, the auxetic polyurethane foam would expand into the PTFE when the foam is stretched, causing contact electrification. Due to a larger contact area between the PTFE and the foam as the foam is stretched, this device can serve effectively as a strain sensor. The sensitivity of this method is explored, and this sensor has the highest sensitivity in all triboelectric nanogenerator devices that are used previously as a strain sensor. Different applications of this strain sensor are shown, and this sensor can be used as a human body monitoring system, self‐powered scale to measure weight, and a seat belt to measure body movements inside a car seat.