Material propertiesDielectric, mechanical and electro-stimulus response properties studies of polyurethane dielectric elastomer modified by carbon nanotube-graphene nanosheet hybrid fillers

The typical nano-carbon materials, 1D fiber-like carbon nanotubes (CNTs) and 2D platelet-like graphene nanosheets (GRNs), that have attracted tremendous attention in the field of polymer nanocomposites due to their unprecedented properties, are used as conducting filler to induce a considerable improvement in the mechanical, thermal and electrical properties of the resulting graphene/polymer nanocomposites at very low loading contents. This study deals with the preparation and electro-stimulus response properties of polyurethane (PU) dielectric elastomer films with such 1D and 2D nanocarbon fillers embedded in the polymer matrix. The various forms of carbon used in composite preparation include CNT, GRN and CNT-GRN hybrid fillers. Results indicate that the dielectric, mechanical and electromechanical properties depend on the carbon filler type and the carbon filler weight fraction. Here, it has been also established that embedding CNT-GRN hybrid fillers into pristine polyurethane endows somewhat better dispersion of CNTs and GRNs as well as better interfacial adhesion between the carbon fillers and matrix, which results in an improvement in electric-induced strain. Therefore, the nanocomposites seem to be very attractive for microelectromechanical systems applications.