Alginate based nanocomposites with magnetic properties

Abstract

Superparamagnetic iron oxide nanoparticles (MNP) were synthesized and incorporated into alginate film forming solutions, leading to composite magnetic films. Both plasticized and non-plasticized films were obtained after casting and drying. It was found that part of the MNP are forming agglomerates or clusters of different sizes into the biopolymeric film, while the remaining ones seem to be perfectly dispersed, being the ratio of these arrangements dependent on nanoparticle and glycerol concentrations. We detected that these particles act also as reinforcements when incorporated into non-plasticized matrices, although present the opposite behavior when dispersed into samples containing glycerol. On the other hand, all composite films behave as super-paramagnetic materials, with increasing saturation magnetization as the content of MNP increases and mean blocking temperatures (<TB>) ranging between 113 and 129 K, which is an expected result due to the strengthening of the dipolar interactions as the size and amount of clusters increase.