Fabrication of multi-layer stacked dielectric elastomer actuator with high output force by co-crosslinking of electrode with DE substrate

As the most promising soft actuator, dielectric elastomer actuator (DEA) possesses high actuated strain and fast response, and thus it finds applications in artificial muscle and soft robot etc. However, the low output force of DEA limits its potential application. The multi-layer stacked DEA is regarded as an effective approach to enhance the output force. Nevertheless, multi-layer stacked DEA fabricated by wet stacking suffers from non-uniformity between layers, while dry stacking suffers from weak interfacial adhesion between layers. Herein, a method for preparation of multi-layer stacked DEA by co-crosslinking of conductive rubber electrode with DE substrate was developed. Titanium dioxide (TiO2)/Polymethylvinylsiloxane (PMVS) composites with simultaneously high dielectric constant, low modulus, high breakdown strength and low dielectric loss were prepared and used as DE substrate, while superconducting carbon black (CB)/Polydimethylsiloxane (PDMS) composites were prepared and used as the vulcanized rubber electrode. By co-crosslinking of electrode with DE substrate, the resultant multi-layer DEA exhibits not only strong adhesion between layers, but also a good stability, combining the advantages of dry stacking and wet stacking. Meanwhile, TiO2/PMVS composite DEA presents a large actuated strain of 50.3% and a high output force of 0.31 N. By stacking three layers of TiO2/PMVS films with electrode, the three-layer stacked DEA can obtain a high output force of 0.88 N and high energy output of 7.14 mJ, 2.84 times and 1.5 times of single layer DEA, respectively. This method provides a new idea for developing multi-layer stacked DEA with higher energy output and output force of DEA.