Synthesis of Hydrophilic Polymer Ligands for Stabilization of Surface of CdSe/ZnS Quantum Dots

The paper presents a method for obtaining hydrophilic CdSe/ZnS quantum dots by replacing the initial low-molecular organic stabilizing ligands on the surface of nanoparticles with polymeric ones. For this purpose, hydrophilic homo- and copolymer based on 2-dimethylaminoethyl methacrylate have been synthesized by the method of radical polymerization with reversible chain transfer (RAFT). Due to the presence of the terminal trithiocarbonate residue of the chain transfer agent (CTA) at the polymer chain, functional thio groups for the interaction with the surface of quantum dots have been obtained. For the possibility of further modification of hydrophilic quantum dots, polymer ligands have been additionally modified with tert-butyl acrylate units, which have been hydrolyzed into functional carboxyl groups. In this study, water-soluble CdSe/ZnS quantum dots have been obtained, coated with new polymer stabilizer ligands bearing several reactive carboxyl groups, which significantly expands the possibilities of application of hydrophilic nanoparticles.