superparamagnetic iron(iii) oxide nanoparticle polymer (SPIONP)： Fabrication and properties

It has been found that the magnetic ground state of nanoparticles can be heavily influenced by the size and macrostructure of the particles, which behave significantly differently from the bulk materials. To obtain superparamagnetic iron particles, co-precipitation technique is applied. Seven different samples (S1-S7) are fabricated under varied conditions by changing the pH value or the reaction temperature. In order to determine the size and properties of the SPIONs manufactured, different electron microscopes and VSM (Vibrating Sample Magnetometers) are applied. S6, which is fabricated at 60°C with pH value 2.75, has the most stable and ideal morphological and magnetic properties.
The idea of producing an elastic magnetic polymer by mixing superparamagnetic iron oxide particles and silicone sealant, Methyltriacetoxysilane and Ethyltriacetoxysilane, termed SPIONP (Superparamagnetic Iron Oxide Nanoparticle Polymer) is proposed to investigate if the distance between the particles can be changed due to the strain applied to enhance their interaction (by direct exchange interaction or dipole interaction) so that they become ferromagnetic or ferrimagnetic. A particle concentration of 30% of the SPIONP pellets was found as the critical locus of particle interaction. The VSM result shows a reduced magnetization after compression. The deformation of the pellets results in a change of distance between the SPIONs in the silicone matrix, which strongly influences the dipole interaction, in another word, the magnetic properties could be altered by stain change of SPIONP.