High-performance wearable strain sensors based on fragmented carbonized melamine sponges for human motion detection

Abstract

Strain sensors based on fragmented carbonized melamine sponges can detect various large and subtle human body motions.

Abstract

Strain sensors with a large strain sensing range and high sensitivity are in high demand due to their various potential applications ranging from human motion detection to soft robotics. In this study, high-performance strain sensors are developed by fragmenting carbonized melamine sponges that are commercially available. The strain sensors, based on fragmented carbonized melamine sponges (FCMS), demonstrate high sensitivity with a gauge factor (GF) of 18.7 at an FCMS density of 1.07 mg cm ⁻² and a large strain sensing range of up to 80%. As a comparison, the strain sensor based on unfragmented carbonized melamine sponges has only a GF of ∼8.0 and limited stretchability (<7%). In situ tension tests indicate that the strain-response mechanism of the sensor is mainly ascribed to the reorientation of individual FCMS at low strains (<40%), while crack propagation dominates the strain-response behavior of the sensor at strains larger than 40%. The high sensitivity and large strain sensing range of the sensor, as well as the low-cost and scalable fabrication method, enable diverse applications. It can not only detect large-strain human arthrosis movements, but it also exhibits the capability to monitor subtle human physiological activity.