High ionic conductive, freezing-resistant and transparent polyurethane based on a novel metal ionic deep eutectic solvent

Abstract

With the progress of society, flexible conductive ionic sensors are becoming more and more important for future advanced wearable devices, for biosensing or human–computer interaction. As the raw element of flexible sensors, the ionic conductive material determines their performance. However, conventional flexible ionic conductive materials always encounter problems of instability and liquid leakage, which greatly limit their practicability. Therefore, in this study, we propose the introduction of a metal ionic deep eutectic solvent (DES) into a polyurethane system via covalent bonding and coordination interaction. This approach has successfully produced an ionic conductive elastomer with excellent properties, including high transparency (92.11%), excellent mechanical strength (66.02 MPa), outstanding electrical conductivity (1.33 × 10⁻⁴ S cm⁻¹), and remarkable low-temperature resistance (−15 °C). The high mechanical strength and electrical conductivity of this elastomer make it promising for flexible sensing applications. In addition, its no-leakage, weatherability, and low-temperature resistance meet a wide range of industrial requirements in daily applications.