Improved the dielectric properties of thermoplastic polyurethane elastomer filled with MXene nanosheets and BaTiO₃ nanofibers

To achieve high deformation under a low electric field intensity is still a big challenge for the dielectric elastomers (DE) potentially used in artificial electronic skin and artificial muscles. Herein, poly-dopamine (PDA) modified 1D barium titanate (BT@PDA) nanofibers and 2D MXene nanosheets with high aspect ratio and large dipole moment were fabricated, and introduced into TPU elastomers. Results showed that the interfacial polarization and micro-capacitor structure formed by MXene sheets lead to the high dielectric constant, and high dielectric loss of MXene/TPU composites with low modulus. The interfacial polarization caused by BT@PDA nanofibers resulting in high dielectric constant and low dielectric loss of BT@PDA/TPU composites with high modulus. Combing the advantages of the two fillers, the MXene/BT@PDA/TPU composites showed high dielectric constant, low dielectric loss, low modulus. The electrical sensitivity factor of 0.5 wt% MXene/5 wt% BT@PDA/TPU composite (11.38) was much higher than the sum of that of 0.5 wt% MXene/TPU (1.73) and 5 wt% BT@PDA/TPU (4.35) composites at a low filler content, showing the 0.5 wt% MXene/5 wt% BT@PDA/TPU dielectric composite had a large deformation under a low electric field. This work can provide an effect strategy to design DE nanocomposites with good deformation performance.