Improved electromechanical properties of silicone dielectric elastomer composites by tuning molecular flexibility

Silicone rubber (SR) composites exhibited significantly improved electromechanical properties via tuning the molecular flexibility by adding plasticizer. To decrease the enhanced elastic modulus of SR composites filled with high-dielectric-constant BaTiO₃ (BT) particles, silicone oil (SO) plasticizer was incorporated into the BT/SR composite to weaken the intermolecular interactions and break the structure of the filler network as result of swelling effect. The obviously decreased elastic modulus resulted in a high electromechanical sensitivity β and a relatively large actuated strain of 10.6% for 20 phr BT/SR composite filled with 50 phr SO at a low electric field of 25 kV/mm, approximately 380% increase compared to that of pure SR at the same electric field. The result indicates that tuning flexibility of composites is a good strategy to obtain high-performance dielectric elastomers.