Fluorinated Ionic Elastomer with Excellent Damping Performance, High Gauge Factor, and Temperature Coefficient of Resistance

Ionic elastomers are strong candidates to fabricate flexible sensors due to their good electrical properties, flexibility, adhesion, and thermal stability. However, external perturbations significantly affect the signal output of ionic elastomer sensors, and the preparation of ionic elastomer sensors with good damping performance is imminent. Herein, ionic elastomers are prepared from chemical crosslinked perfluorohexylethyl acrylate-isooctyl acrylate-hydroxyethyl acrylate (FEA-EHA-HEA) random copolymers and lithium bis((trifluoromethyl)sulfonyl)azanide (LiTFSI). The coexistence of Li+–O and Li+–F coordination, and F–F interaction within the ionic elastomer, was evidenced by the solid-state 6Li and 19F NMR spectra. It also indicated that LiTFSI was enriched in FEA-rich microdomains via F–F interaction, and nanoaggregates were formed with effective coordination of Li+ and F. Thus, the ionic elastomer with an optimized composition exhibited a good room-temperature damping performance with its loss factor up to 1.44 near 34 °C, high gauge factor (1.84 at 0–150% strain), and high temperature coefficient of resistance (up to −704%·°C–1 in the range of 0–5 °C). The above characteristics of the ionic elastomer qualify its multimodal sensing in normal and nonconventional states and its potential applications in intelligent response switching, human–machine interface interaction, electronic skin, and so on.