title: Melt-grafting for the synthesis of core-shell nanoparticles with ultra-high dispersant density.
abstract: Superparamagnetic iron oxide nanoparticles (NPs) are used in a rapidly expanding number of applications in e.g. the biomedical field, for which brushes of biocompatible polymers such as poly(ethylene glycol) (PEG) have to be densely grafted to the core. Grafting of such shells to monodisperse iron oxide NPs has remained a challenge mainly due to the conflicting requirements to replace the ligand shell of as-synthesized NPs with irreversibly bound PEG dispersants. We introduce a general two-step method to graft PEG dispersants from a melt to iron oxide NPs first functionalized with nitrodopamine (NDA). This method yields uniquely dense spherical PEG-brushes (∼3 chains per nm(2) of PEG(5 kDa)) compared to existing methods, and remarkably colloidally stable NPs also under challenging conditions.
authors.affiliation: Institute for Biologically Inspired Materials, Department of Nanobiotechnology, University of Natural Resources and Life Sciences Vienna, Muthgasse 11-II, A-1190 Vienna, Austria. erik.reimhult@boku.ac.at.
authors.forename: Ronald
authors.initials: R
authors.lastname: Zirbs
authors.forename: Andrea
authors.initials: A
authors.lastname: Lassenberger
authors.forename: Iris
authors.initials: I
authors.lastname: Vonderhaid
authors.forename: Steffen
authors.initials: S
authors.lastname: Kurzhals
authors.forename: Erik
authors.initials: E
authors.lastname: Reimhult