2.1 Synthesis of Fe3O4 nanoparticles In a typical synthesis, Fe(acac)3 was added to 20
mL of PEO and heated to reflux for 1 hour under a flow of nitrogen gas until a stable black
suspension was obtained. The concentrations of Fe(acac)3 and volumes of PEO were varied in
order to study their effects on the particles size of Fe3O4 nanoparticles formed.