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The variation of CdSe nanoparticle size as a function of synthesis conditions is presented. Cadmium sulphate (CdSO 4 ), cadmium chloride (CdCl 2 ) and sodium selenosulphate (Na 2 SeSO 3 ) solutions were used as precursors. Nanoparticles were synthesized by aqueous chemical methods. The synthesis parameters studied were pH, Cd:Se ratio and the type of stabilizing agent. Three different stabilizing agents were used, thioglycolic acid, mercaptoethanol and poly(vinyl pyrrolidone). Fourier transform infrared spectroscopy results confirmed the presence of the stabilizing agent on the surface of the nanoparticles. Ultraviolet visible and X-ray powder diffraction measurements were used to estimate the trend of size variations of the particles with different synthesis parameters, which agreed fairly by both techniques and the crystal structure. Additionally, the size of the nanoparticles was obtained by transmission electron microscopy measurements. Whilst the effect of pH was different for each of the different stabilizing agents due to the different chemical groups in the thiol compounds and the size of the nanoparticles varied with the used stabilizing agents, the effect of Cd:Se ratio in the size of nanoparticles showed the same tendency for the several stabilizing agents.

Continuing with our previous work, in which CdSe nanoparticles were functionalized with polystyrene (PS) brushes (CdSe-PS) by grafting through method, nanocomposites 2 were prepared by adding them to a poly (styrene-b-butadiene-b-styrene) (SBS) triblock copolymer. After characterizing CdSe-PS nanoparticles obtained at different polymerization times of 3, 5 and 8 h by means of thermogravimetric analysis (TGA) and gel permeation chromatography (GPC), CdSe-PS nanoparticles obtained after 5 h of polymerization (CdSe-PS(5h)) were chosen as the most adequate for the generation of nanocomposites. Atomic force microscopy (AFM) was used for morphological characterization of SBS/CdSe-PS (5h) nanocomposites. AFM images showed a good dispersion of the nanoparticles in the block copolymer, with the placement of the nanoparticles in the PS domains due to the improved affinity obtained by their functionalization with PS brushes.