Improved electro-actuation of polydimethylsiloxane-based composite dielectric elastomer via constructing semi-interlocked dual-network

Abstract

Dielectric elastomer (DE) has a pivotal potential in various applications as a typical electro-active polymer. However, traditional DE materials often require high electric fields to achieve an excellent electro-actuated performance, which severely restricts their practical applicability. In this study, vinyl methyl silicone (VMQ) macromolecular chains are introduced as the highly-viscous plasticizer to reduce the elastic modulus of polydimethylsiloxane (PDMS)-based DE composites. The bisilane-modified TiO₂ nanoparticles (mTO) that grafted by thiols and octadecane are incorporated to increase the dielectric constant of DE composites. The synergistic effects contributed by these components give rise to a notable improvement in the electro-actuated performance of DE composites. Moreover, the thiol-ene click chemical reaction between the functional groups on mTO and VMQ makes the formation of a semi-interlocked cross-linked network structure within the PDMS-based elastomers. This network effectively mitigates the issue of plasticizer leaching during the long-term utilization of DE composites. The PDMS-based composite comprising 10 wt% mTO and 20 wt% VMQ achieves a remarkable electro-actuated strain of 72.5% at 65.4 V/μm, representing a 539% increase compared to pure PDMS (∼18.6%). This study provides an effective strategy for developing advanced DE composites with high electro-actuated properties at low electric fields.