Ultrastretchable, Tough, and Highly Conductive Ionogels for Multipurpose Motion Monitoring

Abstract

Stretchable strain sensors have attracted considerable interest for electronic and electrochemical applications, but improving their sensitivity, stretchability, toughness, conductivity, and stability remains a challenge. While ionic conductor-based sensors offer high stretchability (>100%), achieving both robustness and high conductivity is difficult. In this study, ultrastretchable, tough, and highly conductive nonvolatile polymer electrolytes, referred to as ionogels, were devised using a solvent-exchange method. Compared to other gel-type materials, such as organogels and hydrogels, the ionogels exhibit outstanding elasticity (>1000% strain at break), toughness (∼100 MJ m^–3), and ionic conductivity of (∼20.5 mS cm^–1). These ionogels were successfully applied to sensing devices, and the resulting sensors exhibited excellent linearity, sensitivity, repeatability, and operational durability. Furthermore, the sensors accurately detected the movements of various vehicle parts, including the suspension damper, door hinge, and seat coil, indicating the potential of mechanically tough ionogels for multipurpose sensing systems.