Polydimethylsiloxane-α,ω-diols were used as matrix for barium titanate particles to obtain electroactive elastomeric composites. Filler particles were previously treated with a surfactant to improve the compatibility with and dispersibility in the matrix. The composites, processed as films and crosslinked with methyltriacetoxysilane, were investigated from point of view of the morphology, moisture sorption and thermal properties, as well as mechanical and dielectric behavior. Maximum strain value of 850% at 0.32 MPa and dielectric permittivity of 4.41 at 10 Hz and 20 °C were obtained. Two parameters of interest for potential future application of such materials in electromechanical devices (actuation or harvesting), electromechanical sensitivity and harvesting energy capacity, were estimated and discussed in correlation with the molecular mass of the polymeric matrix and the content of the active filler

Polyether urethane (PU)-based magnetic composite materials, containing different types and concentrations of iron oxide nanostructures (Fe₂O₃ and Fe₃O₄), were prepared and investigated as a novel composite platform that could be explored in different applications, especially for the improvement of the image quality of MRI investigations. Firstly, the PU structure was synthetized by means of a polyaddition reaction and then hematite (Fe₂O₃) and magnetite (Fe₃O₄) nanoparticles were added to the PU matrices to prepare magnetic nanocomposites. The type and amount of iron oxide nanoparticles influenced its structural, morphological, mechanical, dielectric, and magnetic properties. Thus, the morphology and wettability of the PU nanocomposites surfaces presented different behaviours depending on the amount of the iron oxide nanoparticles embedded in the matrices. Mechanical, dielectric, and magnetic properties were enhanced in the composites’ samples when compared with pristine PU matrix. In addition, the investigation of in vitro cytocompatibility of prepared PU nanocomposites showed that these samples are good candidates for biomedical applications, with cell viability levels in the range of 80–90%. Considering all the investigations, we can conclude that the addition of magnetic particles introduced additional properties to the composite, which could significantly expand the functionality of the materials developed in this work.