Highly conductive and rapidly self-healing aqueous polyurethane ionogel skin based on ionic dipoles of IL

Abstract

In today’s burgeoning e-skin trend, ionic liquids (IL) have been incorporated into polymer substrates in significant quantities due to their high conductivity and stability. However, the high substitution resistance of IL is often impeded by the polymer substrates, leading to reduced carrier mobility and sensitivity. Here, we designed a self-healing waterborne polyurethane (WPU) with a polydimethylsiloxane (PDMS) backbone and prepared WPU ion gels through complexation with IL. The increased mobility of the PDMS fragments reduces the glass transition temperature (Tg) and crystallinity of the WPU and increases the carrier transport rate of IL in the WPU substrate, thus improving the electrical conductivity. Additionally, the exchange of disulfide bonds within the backbone, along with ion–dipole interactions, facilitates the rapid repair of the ionic gel when fractured, occurring within five minutes. The resulting ionic gels possess the capability to detect subtle human motion signals, such as facial expressions, heartbeats, and muscle movements.