Preparation of hexagonally aligned inorganic nanoparticles from diblock copolymer micellar systems

The aim of this work was to prepare hexagonally aligned zinc oxide nanoparticles using poly(styrene)-block-poly(2-vinyl-pyridine) block copolymer spherical micellar system. Various zinc salt were used with different zinc ion/pyridine unit ratio (loading factor, L) to obtain patterned surface. The loaded micelles were deposited on surface of silicon wafer by immersion method. Oxygen plasma treatment was used to generate nanoparticles in periodic patterns on the surface of Si-substrate. The morphology of the loaded micelles and the particles were studied by transmission electron microscopy (TEM) and atomic force microscopy (AFM). The chemical composition and the crystalline structure of samples were investigated by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) measurements, respectively. On basis of the results of the XPS and XRD measurements we assumed that during the plasma treatment the zinc precursor salt reacted with the oxide layer on the surface of the silicon wafer and formed zinc silicate (Zn₂SiO₄) instead of ZnO nanoparticles.