Aggregation of dextran coated magnetic nanoparticles in aqueous medium: Experiments and Monte Carlo simulation

Number density distribution of aggregates of dextran coated superparamagnetic iron oxide (Fe3O4) nanoparticles in an aqueous medium has been predicted using Monte Carlo simulation, and compared with our and others’ experimental data on aggregates. In addition to van der Waals and magnetic attraction between particles, the simulation included both bridging attraction and steric repulsion due to the presence of dextran on the nanoparticle surface. The simulation methodology is system independent and gave very good agreement with experimentally observed extensive aggregation in dextran coated particles – both for a wide range of molecular weight of dextran and different diameter and volume percentage of individual Fe3O4 nanoparticles.