Synergistic enhancement of mechanical and magnetorheological properties in silicone-based MR elastomers by carbon nanotube-silica hybrid reinforcement

Abstract

Magnetorheological elastomers (MREs) are smart materials that exhibit adjustable mechanical properties under external magnetic fields and are widely used in soft robotics and biomedical devices. Traditional MREs are composed of magnetic fillers and elastic matrices, and their mechanical strength and magnetorheological response have received widespread attention from researchers. In this context, this study investigates the synergistic reinforcement effects of carbon nanotubes (CNTs) and silica (SiO₂) nanoparticles on the mechanical and magnetorheological properties of silicone-based MREs. A series of MREs samples were fabricated with varying concentrations of CNTs and SiO₂, both individually and in combination. Their mechanical behavior under static and magnetic field conditions was systematically analyzed through tensile tests, stress relaxation experiments, and elastic modulus measurements. Microstructural characterization revealed that CNTs tend to form interconnected networks, enhancing tensile strength, while SiO₂ improves filler dispersion and interfacial bonding, contributing to greater elongation at break and stability. The combined addition of CNTs and SiO₂ exhibited a synergistic effect, with the hybrid-filled sample SC204-MREs achieving a tensile strength of 3.95 MPa and enhanced field-induced modulus variation. Moreover, the composite demonstrated reduced stress relaxation and improved magnetic responsiveness, confirming that optimized hybrid fillers can overcome the trade-off between stiffness and magneto-mechanical sensitivity. These findings provide a promising strategy for the development of high-performance, field-responsive elastomeric composites.