title: Functionalization of magnetic nanocrystals by oligo (ethylene oxide) chains carrying diazonium and iniferter end groups.
abstract: The water stability of iron oxide nanoparticles (NPs) is a major issue for biomedical and biological applications. This paper presents a versatile approach for preparing water-soluble iron oxide nanoparticles coated by bifunctional oligo(ethylene oxide) (OEO) chains, carrying on the one side a diazonium end group for covalent grafting at the NP surface and on the other side an iniferter group (diethyl dithiocarbamate) for initiating the growing of poly(methacrylic acid). The nanoparticles were synthesized by coprecipitation in basic media and functionalized in situ by adding the diazonium salt directly in the synthesis medium. Oligo(ethylene oxide) with various chain lengths (from one to three monomer units) was grafted at the NP surface using this approach. The length of the OEO spacer between the NP surface and the iniferter end group was found to be a critical parameter for controlling the colloidal stability of the hybrid NPs. The polymerization time was also shown to strongly influence their colloidal stability, emphasizing the interest to control the interfacial properties of the hybrids for obtaining stable dispersions in water.
authors.affiliation: Univ Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France.
authors.forename: Randa
authors.initials: R
authors.lastname: Ahmad
authors.forename: Nébéwia
authors.initials: N
authors.lastname: Griffete
authors.forename: Aazdine
authors.initials: A
authors.lastname: Lamouri
authors.forename: Claire
authors.initials: C
authors.lastname: Mangeney
mesh_terms: D005027:Ethylene Oxide / Q000737:chemistry*; D008280:Magnetics; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry; D014961:X-Ray Diffraction
chemical_list: D005027:Ethylene Oxide
keywords: Colloidal dispersion; Diazonium salts; Nanoparticles; Polymer grafts