Layer-by-layer assembly of polyacrylate-capped CdS nanoparticles in poly(diallyldimethylammonium chloride) on solid surfaces

Polyacrylate-capped CdS nanoparticles were synthesized and self-assembled layer-by-layer in poly(diallyldimethylammonium chloride) on different surfaces, by virtue of the Coulombic attraction between the negatively charged polyacrylate surface capping agent and the cationic polyelectrolyte. High-resolution TEM imaging and electron diffraction measurements revealed the growth of 3-4 nm size CdS quantum crystallites, having a zinc blende lattice structure. TEM images of the assembled films provided evidence of the incorporation of the Q-particles and showed their distribution in the polyelectrolyte matrix. The layer-by-layer assembly of Q-CdS in the polymer by means of consecutive surface-charge reversal was characterized using UV-visible absorption, photoluminescence, Fourier transform infrared spectroscopy, and ellipsometry. Results revealed a uniform charge reversal and a linear assembly of not more than a monolayer of polyacrylate-capped nanoparticles at each step.