A mussel-like inspired modification of BaTiO3 nanopartciles using catechol/polyamine co-deposition and silane grafting for high-performance dielectric elastomer composites

The molecular structure of high-dielectric-constant BaTiO3 nanoparticles was tailored via mussel-like inspired modification using catechol/polyamine co-deposition and subsequent silane gamma-(2,3-epoxypropoxy)-propy-trimethoxysilane (KH560) grafting (denoted as BT-PCPA-KH560) to improve the electromechanical properties of natural rubber (NR) dielectric elastomer composites. The epoxy groups in KH560 provided sufficient anchor points for chemical bonding with NR rubber matrix during the vulcanization process, resulting in an improved dispersion and enhanced interfacial interaction. As a result, the BT-PCPA-KH560/NR composites displayed enhanced mechanical, dielectric, and electromechanical properties. A large actuated strain of 13.4% was achieved by the 50 phr BT-PCPA-KH560/NR composite, which is similar to 2.2 times higher than the largest actuated strain of pure NR (6.0%). Moreover, the 50 phr BT-PCPA-KH560/NR dielectric composite displayed high stability with cycles and high electric breakdown field, which is beneficial for preventing the premature failure of dielectric elastomer actuator. As compared with poly(dopamine) deposition, the proposed approach is more efficient and cost-effective, and may have potential applications in industry.