Encapsulation of semiconductor quantum dots into the central cores of block copolymer cylindrical and toroidal micelles

Abstract

The formation of well-defined nanoparticles-loaded cylindrical micelles is of considerable interest to the development of nanomaterials with desired optical, electric, magnetic, and mechanical properties. Herein, encapsulation of monodisperse polystyrene (PS)-grafted CdSe/CdS quantum dots (QDs) within the PS cores of PS-b-PEO cylindrical and toroidal micelles proceeded through dispersion of both the QDs and PS-b-PEO in a good solvent (DMF) then simultaneous desolvation of QDs and PS block of the copolymer by addition of water. We demonstrated the effects of water content and stirring time on the morphologies of hybrid assemblies and found that the cylindrical and toroidal micelles with QDs uniformly encapsulated into the central cores were preferentially formed at the block copolymer initial concentration of 2 wt%, water content of 6 wt% and stirring time of 5–7 days. Additionally, two different formation pathways of the hybrid cylindrical micelles were demonstrated. Moreover, the colloidal aqueous solution of hybrid assemblies exhibit highly emissive properties as compared to the unmodified QDs, which have potential application in biological targeting and fluorescence labeling.