Radiofrequency characterization of polydimethylsiloxane - iron oxide based nanocomposites

Colloidal iron oxide nanoparticles with diameters ranging from 15 +/- 1 nm up to 29 +/- 3 nm are used as pure dielectric fillers for nanoparticles-doped nanocomposites. We show that their superparamagnetic behavior allows them to increase the real dielectric constant of polydimethylsiloxane keeping unchanged the magnetic permittivity. Moreover, all the realized nanocomposites (concentration up to 8 wt.%) show very low dielectric and magnetic losses, suggesting that, at the investigated concentrations, the proposed material tan be used as a substrate for electromagnetic circuits in the frequency range between 0.5 GHz and 2.5 GHz. (C) 2012 Elsevier B.V. All rights reserved.