Design and structural features of magnetic cobalt ferrite nanoparticles in a biopolymer matrix

Nanostructured cobalt ferrites were obtained by chemical condensation in a one-pot synthesis under environmentally acceptable conditions. Narrowly dispersed cobalt ferrite nanoparticles were formed in the presence of a dielectric matrix of the natural polysaccharide arabinogalactan. It is shown that the size-controlled stabilization and guided self-organization of nanocomposites is due to the unique nature of the chosen polymer matrix. Modification of the nanoparticles surface with a hydrophilic polysaccharide promotes a uniform spatial distribution of nanoparticles in the bulk of the nanocomposite. The structural characteristics of NCs were studied using XRDMA, IR spectroscopy, TEM and X-ray diffractometer. The inorganic phase of the obtained samples with varying cobalt content has a cubic spinel structure with an average crystallite size of 6.5–12.5 nm. The electron paramagnetic resonance method was used to study the magnetic properties of nanocomposites and their changes with increasing temperature in the range of 25–125°C. It was shown for the first time that heating the nanocomposites directly in the spectrometer resonator significantly enhances the integral intensity of the EPR spectrum signal with a significant variation in the line width and [Formula: see text]-factor. It was established that the degree of substitution of iron by cobalt in obtained nanocomposites played a key role in changing the interaction of samples with a magnetic field. Presumably, the shape of the spectrum changes when the temperature rises to 125°C due to the transformation of multi-domain particles into single-domain particles due to the displacement of domain boundaries. The resulting water-soluble nanocomposites, combined with a biocompatible polymer matrix, have a unique set of properties and, as a result, are potentially interesting for classical and new applications in technological fields, from electronics to biomedicine.