Flexible strain sensor with self-healing function for human motion monitoring

Abstract

Flexible strain sensors with highly similar effects to human skin have been given great attention due to their potential application in personal health monitoring, human–computer interaction systems and artificial electronic skin fields. In particular, the self-healing properties of the sensors are important for their long-term and repeated use during the actual operation. Herein, a flexible strain sensor with complete self-healing function is proposed by combining self-healable PDMS film with rich hydrogen bonds and conductive ink based on recoverable liquid metal. By adjusting the contents of different components of self-healing PDMS film and the relative mass fraction of the liquid metal ink in the strain sensor, the tensile stress and resistance of flexible sensor can be changed to match different usage scenarios. The sensor can achieve a maximum tensile stress of 0.83 MPa and an elongation at break of 843%. After self-healing for 24 h at room temperature, its tensile stress can revert to 82% of the original value, while the electrical connection can instantaneously recover to initial situation after fracture surface contacts. This hints its potential advantage as wearable sensors for motion monitoring of the human body and developable applications in medical monitoring, recyclable electronics and artificial skin.