Surface modification of γ-Fe2O3 nanoparticles by grafting from poly-(hydroxyethylmethacrylate) and poly-(methacrylic acid): Qualitative and quantitative analysis of the polymeric coating

Abstract Superparamagnetic maghemite, γ-Fe 2 O 3 nanoparticles (NPs) were produced by the so-called polyol process and subsequently coated by different hydrophilic polymers, namely the poly-(hydroxyethylmethacrylate) and the poly-(methacrylic acid), using atomic transfer radical polymerization (ATRP), leading to stable colloids in water. The resulting nanohybrids were considered as biocompatible smart multifunctional nano-tools for magneric resonance imaging (MRI), magnetic hyperthermia or magnetically stimulated drug release. The intermediates obtained in the different steps of chemical surface functionalization, as well as bare NPs and the final magnetic nanohybrids, were characterized by various techniques including infrared spectroscopy, thermogravimetry, X-ray photoelectron spectroscopy, transmission electron microscopy, dynamic light scattering and magnetometry with a special emphasis on the quantification of the polymer brushes grafting density.