A Versatile Synthetic Approach to Covalent Binding of Polymer Brushes on CdSe/CdS Quantum Dots Surface: Multitype Modification of Nanocrystals

A novel and versatile approach to the preparation of multitype polymers brushes on the quantum dots surface is reported. In this method, an azo initiator is first immobilized covalently onto CdSe/CdS particle surface by reacting with the 4,4'-Azobis (4-cyanovaleric acid) through an ester linkage. CdSe/CdS nanoparticles with polymer brushes (CdSe/CdS-polymers) of different properties, including hydrophilic polyacrylamide, poly(acrylic acid), and poly(vinyl pyrrolidone); hydrophobic oleophilic poly(vinyl acetate), poly(methyl acrylate), and poly(methyl methacrylate); polystyrene with conjugate group; and polyacrylonitrile with strong polarity group, are synthesized by one approach (the surface-initiated radical poly merization technique), respectively. The structures and properties of CdSe/CdS-polymers reveal that the CdSe/CdS-azo initiator has excellent ability to initiate various kinds of vinyl monomers and these synthetic CdSe/CdS-polymers exhibit good stability and can emit multiple colors from the emission 405 to 569 nm. Moreover, CdSe/CdS-polymers brushes show characteristic micromorphologies. Such strategy provides a platform to achieve nanocomposites with different properties by a new CdSe/CdS-azo initiator through the simple conventional radical polymerization technique. Besides, the synthetic approach gives access to multitype modification of different nanoparticles with polymers.