Preparation and characterization of superparamagnetic Fe₃O₄ nanoparticles modified by P(AA-co-MPC)

A series of copolymers (P(AA-co-MPC)) with acrylic acid (AA) and 2-methacryloy-loxyethyl phosphorylcholine (MPC) monomers were synthesized via RAFT polymerization. Then the magnetic iron oxide nanoparticles were modified by these synthesized copolymers through chemical coprecipitation method. Copolymers and the nanoparticles were characterized by 1H NMR, FTIR, GPC, TG, TEM, XRD, Zeta potential and particle size analyser, and Squid-VSM magnetic measure system. The results show that the P(AA-co-MPC) with narrow molecular mass distribution is successfully synthesized by RAFT polymerization and the surface of the magnetic iron oxide nanoparticles is modified by these copolymers. The modified magnetic iron oxide nanoparticles by copolymer synthesized with the monomer molar ratio of AA:MPC of 1:1 exhibit the best dispersion, the smallest hydrodynamic particle size (36.54±4.00) nm, the narrowest particle size distribution and the highest Zeta potential (-30.98±1.25) mV. The saturation magnetization is 65.57A·m2·kg-1. The nanoparticles show superparamagnetism, with no residual magnetism and zero coercive force