Modulation of Spacing and Magnetic Properties of Iron Oxide Nanoparticles through Polymer-Mediated "Bricks and Mortar" Self-assembly

Polymer-mediated "bricks-and-mortar" self-assembly of (gama)-Fe2O3 nanoparticles allows modulation of the structure and magnetic properties of the resulting nanoparticle assemblies. Noncovalent assembly of thymine-functionalized nanoparticles using diaminotriazine-functionalized polystyrene provides extended aggregates featuring enhanced ordering relative to control samples of unassembled particles. In addition, the polymer-assembled aggregates feature increased interparticle spacing arising from the polymer "mortar". The enhanced ordering and increased spacing provided by the polymer-mediated assembly alters the strength of interparticle coupling, as manifested by characteristic changes in the magnetic properties of the assemblies