Enhanced electromechanical properties of natural rubber using highly efficient and cost-effective mussel-inspired modification of TiO2 nanoparticles

Recently, dopamine and its secondary function are being used as the intermediate to tailor the surface molecular structure of high-dielectric-constant nanoparticles , which improves interfacial interaction of dielectric elastomer (DE) composites, due to their versatile adhesion properties. However, the high-cost of dopamine limits the large-scale applications of DE. Herein, a mussel-inspired modification of TiO 2 nanoparticles is presented to prepare high-performance natural rubber (NR) DE composites by replacing dopamine with cheaper poly(catechol/polyamine) (PCPA). First, the TiO 2 nanoparticles were deposited with PCPA. Then, the PCPA-coated TiO 2 nanoparticles were further grafted with γ-methacryloxypropyl trimethoxy silane (KH570), which contains double bonds and denoted as TiO 2 -PCPA-KH570. Owing to the presence of C C bonds, the TiO 2 -PCPA-KH570 nanoparticles participated in the vulcanization of NR and the TiO 2 -PCPA-KH570/NR composites exhibited enhanced filler dispersion and interfacial interaction, leading to the improved mechanical, dielectric, and electromechanical properties. Furthermore, the 10 phr TiO 2 -PCPA-KH570/NR composite resulted in the largest actuated strain of 12.3%, which is ~2 times higher than that of the largest actuated strain of pure NR (6.0%). The present study provides a high-efficient and cost-effective route to obtain DEAs with enhanced electromechanical properties.