Fe3O4 nanoparticles coated with homopolymers of glycerol mono(meth) acrylate and their block copolymers

Highly stable aqueous magnetic fluids were prepared by coating Fe3O4 nanoparticles with poly( glycerol monoacrylate), poly( glycerol monomethacrylate), or diblock copolymers, poly( acrylic acid)-b-poly( glycerol monoacrylate), poly[(N, N-dimethylamino) ethyl methacrylate]b-poly( glycerol monomethacrylate) or poly( ethylene glycol) monomethyl ether-b-poly(glycerol monoacrylate). These homopolymers and block copolymers were synthesized by atom transfer radical polymerization. These dispersions were stable in 10% NaCl, 10% CaCl2, or in wide pH ranges. In these magnetic fluids, poly(glycerol monoacrylate) or poly( glycerol monomethacrylate) were chemisorbed onto the Fe3O4 nanoparticle surface through their 1,2- diol groups by forming five-membered chelate rings with the Fe atoms, while the other blocks in the cases of the block copolymers as the stabilizers extended into the water matrix. Thus the nanoparticles prepared with these three block copolymers mentioned above respectively contain negatively charged, positively charged or uncharged and biocompatible surfaces under physiological conditions. This procedure provided a good choice for preparing stable magnetic fluids with tailored surfaces and/ or tailored functional groups on the surfaces of the magnetic nanoparticles.