Improved electro-actuation performance of polyurethane-based dielectric elastomer under ultra-low electric fields via introducing soft functional filler

Abstract

Dielectric elastomers (DEs) show promise in applications such as soft robots, artificial muscles, and sensors due to their large actuation strain and high energy density. However, such large actuation strains in DEs are typically achieved under relatively high driving electric fields, which limits their practical applications, particularly in biomedicine and healthcare fields. Consequently, obtaining excellent electro-actuated strain under ultra-low electric fields is a significant challenge for DEs. Herein, an acrylate-based copolymer (defined as C-PEG) was introduced into the thermoplastic polyurethane (TPU) matrix as a soft filler. The intermolecular hydrogen-bonding interactions between C-PEG and the TPU matrix can weaken the hydrogen-bonded cross-linking network of TPU, thereby reducing the Young's modulus of the composites. Furthermore, the inherent polar groups of C-PEG and the hydrogen-bonding interactions between C-PEG and TPU can further enhance the polarization ability of the composites. The results show that the C-PEG/TPU composite achieves an actuation strain of 10.8% under ultra-low electric fields (10 V/μm), which is 468.9% higher than that of pure TPU. Therefore, this study presents a promising approach for fabricating novel DEs with superior electro-actuated properties under ultra-low electric fields.