Electromagnetic, magnetorheological and stability properties of polysiloxane elastomers based on silane–modified carbonyl iron particles with enhanced wettability

Soft carbonyl iron (CI) particles were successfully modified with a thin layer of tetraethoxysilane (TEOS) to enhance the wettability of their surface in hydrophobic media. The contact angle investigations and tensiometric analysis revealed and helped quantify the significantly enhanced wettability and, thus, the better interfacial adhesion of the TEOS–coated CI particles (CI–TEOS) with the non–polar siloxane–based materials. Therefore, stable magnetorheological elastomers (MREs) based on CI–TEOS particles and polydimethyl siloxane matrix were fabricated. The prepared composites had different particle loadings and microstructural characteristics: isotropic and anisotropic. These structural differences were confirmed by scanning electron microscopy and were found to considerably affect dielectric properties of the MREs due to various charge transport mechanisms within the particle clusters. Furthermore, the magnetorheological (MR) performances of isotropic MRE variants were analysed before and after exposure to acidic environment. After the corrosion test, the MRE based on bare CI particles exhibited dramatically decreased relative MR effect and mechanical properties when compared with its analogue containing CI–TEOS. (paper)