Effects of graphene oxide on microstructure and mechanical properties of isotropic polydimethylsiloxane-based magnetorheological elastomers

Isotropic magnetorheological elastomers (MREs) with carbonyl iron particles (CIPs) dispersed in graphene oxide (GO)–filled polydimethylsiloxane (PDMS) matrix were fabricated by using the solution blending-casting method. The effects of GO content on the microstructure, vulcanization, quasi-static compression, and dynamic magnetorheological (MR) effect were experimentally investigated. The results reveal that the addition of GO sheets hinders the chemical cross-linking of PDMS matrix and induces the loose interphase layers between GO sheets and the PDMS matrix. The changing of mechanical properties according to GO loading is controlled by two competing factors: the inhibited chemical cross-linking of PDMS chains and the reinforcing effect of GO sheets. Under the quasistatic compressive load, the former is the dominant factor and causes the decrease of the compressive modulus. Under the dynamic shear deformation, the latter is the dominant factor and leads to the increment of the dynamic shear modulus. The increase in the GO content can lead to the increase of the weak GO/PDMS interfaces and particle aggregations, which in turn cause the improved Payne effect and loss modulus. The MR effect of the MREs under the magnetic field is improved by GO loading due to the enhanced mobility of CIPs in the GO-filled PDMS matrix. Graphical abstract