A conductive and self-healing polyurethane based on coordination interactions with wide-adjustable mechanical properties for flexible sensors

Abstract

Polyurethane elastomers were considered as an ideal material for flexible devices. However, the application of polyurethane elastomers was still largely limited by the disadvantages of poor self-healing property and low conductivity. In this work, a self-healing polyurethane with adjustable mechanical performances was constructed via the introduction of reversible dynamic interactions in the polyurethane matrix, such as metal ion-tripyridine coordinations, disulfide bonds and hydrogen bonds. And lithium salt was incorporated into the polyurethane to achieve ionic conductivity. The obtained polyurethane exhibited adjustable breaking strength with a range of 0.77 ∼ 10.75 MPa, breaking elongation in the range of 1719 ∼ 1863 %, and conductivity in the range of 0.08 ∼ 1.57 × 10−3 S/m by adding different LiTFSI (5 ∼ 35 wt%) into the polyurethane. In addition, the polyurethane displayed efficient self-healing behavior, well fatigue resistance, and recyclability. Also, the polyurethane showed great application prospects as flexible sensors by performing stable and sensitive responses to a wide range of human body movements.