Polyol made from about 10 nm sized maghemite nanoparticles was functionalized by a hydrophilic catechol derivative, namely, dopamine. Infrared spectroscopy confirmed the grafting, whereas X-ray diffraction and transmission electron microscopy did not show either structural or microstructural change on the iron oxide particles. 57Fe Mössbauer spectrometry allowed, giving a quantitative assessment of the bonding preferences of dopamine on the iron oxide surfaces, the π-donor character of this ligand to be experimentally evidenced for the first time. These results are supplemented by ab initio modeling, expanding on previous work by considering various iron oxide surfaces and orientations. Perspectives of the work are discussed.

We propose the elaboration and study of rheological properties under continuous magnetic field of magnetic sensitive biopolymer-based nanocomposites. Magnetic iron oxide (maghemite) nanoparticles were synthesized by the polyol process and then functionalized by grafting organic bifunctional ligand for establishing electrostatic bonds between the sodium alginate chains of biopolymer and functionalized nanoparticles. The enhancement of rheological properties at low shear rate of these new magnetic soft nanocomposites was clearly demonstrated by the increase of yield stress and viscoelastic moduli in the linear viscoelastic domain with an increase of applied magnetic field, thus providing new functionality to these soft nanocomposites.