Catechol-derivatized poly(vinyl alcohol) as a coating molecule for magnetic nanoclusters

• We prepared well-defined polymer coated magnetic nanoparticles.
• We used polyvinyl alcohol (PVA) as an alternative to commonly used plyethylene glycol (PEG).
• We strongly anchored the polymer on the magnetic nanoparticles׳ surfaces.
• We developed a one-pot emulsion ligand exchange process.
• We obtained single coated particles and well defined magnetic clusters, which we successfully separated.

Surface functionalization of superparamagnetic iron oxide nanoparticles (SPIONs) remains indispensable in promoting colloidal stability and biocompatibility. We propose a well-defined and characterized synthesis of a new catechol-functionalized RAFT (reversible addition–fragmentation chain transfer) poly(vinyl alcohol) polymer, which can be anchored onto hydrophobic SPIONs via a one-pot emulsion ligand exchange process. Both single and clustered nanoparticles are obtained and can be separated from each other. As clustered SPIONs are receiving increasing attention, this new macroligand might be of considerable interest for both basic and applied sciences.