Polysulfide polyurethane–urea-based dielectric composites with CeO2-loaded MXene exhibiting high self-healing efficiency

To overcome the effect of high actuation voltages causing dielectric elastomer films to breakdown, fabricating films with excellent dielectric properties and high durability is the current focus. Previously reported dielectric elastomer films, nevertheless, still require better dielectric properties and suffer from a lack of self-healing properties, which reduces the service life of the films. In this work, polysulfide polyurethane–urea (PSPU) elastomers with self-healing properties were synthesized through the insertion of dynamic disulfide bonds into the polymer chain segments via hydrogen transfer reactions. In addition, PSPU-based composites were fabricated in which the filler was MXene loaded with CeO2 obtained using a hydrothermal method. Benefiting from dynamic disulfide bonding and multiple hydrogen bonding interactions, PSPU attained a self-healing efficiency of 95%. Moreover, the 5.25 vol% CeO2@MXene/PSPU composite exhibited a dielectric constant of 206 at 100 Hz, maintaining a loss of 0.19 while having a self-healing efficiency of 97.9%. In contrast to PSPU, the dielectric constant of 5.25 vol% CeO2@MXene/PSPU was 34 times higher than that of the former at 100 Hz. These distinctive properties promise to render the films an integral part of the actuator.