Controlled placement of polystyrene-grafted CdSe nanoparticles in self-assembled block copolymers

Abstract

Surface functionalization of semiconductor CdSe nanoparticles has been achieved with polystyrene (PS) brushes by “grafting from” technique for further addition to a polystyrene-b-polybutadiene-b-polystyrene (SBS) block copolymer in order to obtain self-assembled composites. For modification of nanoparticle surface 3-glycidoxypropyltrimethoxysilane (GPS) was used at first for the later attachment of the 4,4´-azobis(4-cyanopentanoic acid) (ACP) azo initiator. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of GPS and PS on the surface of nanoparticles. Atomic force microscopy (AFM) was used for morphological characterization of SBS/CdSe nanocomposites. Modification of nanoparticles with PS brushes by radical polymerization improved their affinity with PS block and the dispersion of nanoparticles avoiding agglomeration. CdSe nanoparticle size was measured to be around 2 nm by the use of X-ray diffraction (XRD) and UV-vis techniques. Optical properties were characterized using fluorescence measurements.