Optical, structural and adsorption properties of zinc peroxide/hydrogel nanohybrid films

Department of Physical Chemistry and Materials Sciences, University of Szeged, H-6720 Szeged, Hungary; Supramolecular and Nanostructured Materials Research Group of the Hungarian Academy of Sciences, H-6720 Szeged, Aradi v.t. 1. Hungary
Applied Surface Science (Impact Factor: 2.54). 06/2010; DOI: 10.1016/j.apsusc.2009.12.075

ABSTRACT Hybrid nanofilms from zinc-peroxide/poly(acrylamide) (ZnO2/PAAm) and zinc-peroxide/poly(N-isopropyl-acrylamide) (ZnO2/PNIPAAm) were prepared using the photopolymerization procedure. The thin layers were prepared by the combination of the Layer-by-Layer (LbL) self-assembly method and photopolymerization using UV light in every step of the procedure. The hybrid multilayer films consisting of layers of zinc peroxide nanoparticles and hydrogel alternating in a sandwich-like fashion with thicknesses of 65–246 nm. The chemical structures of the hybrid films were investigated by FTIR spectroscopy, their morphology was studied by atomic force microscopy (AFM). The build up of the films was studied by measuring the optical reflection spectrum, and we have calculated the refractive index and layer thickness of the hybrid layers using simulating software. The adsorption properties of the ZnO2/hydrogel nanohybrid composite networks were investigated by measuring water and ethanol vapour adsorption by a quartz crystal microbalance (QCM). It was established that on partially hydrophobic ZnO2/PNIPAAm hybrids the adsorbed amounts were lower, against the hydrophilic ZnO2/PAAm film the vapour amount was higher. These results correspond to those of the bulk gel swelling results.

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    ABSTRACT: The surface treatment with boiling hydrogen peroxide (H2O2) solution on the surface of ZnO nano-columnar film was investigated. Field emission-SEM and TEM analysis revealed that amorphous ZnO2 layer covers the ZnO nano-column surface through the H2O2 treatment at 100°C for 1 min. X-ray photoemission spectroscopy (XPS) has been conducted on the H2O2 treated ZnO surface. The surface exhibits high resistive conductivity after the H2O2 treatment, suggesting that the treatment promotes a compensation effect. We demonstrate that dramatic improvement in the rectifying behavior on the Schottky diodes can be achieved by inserting a ZnO2 interface layer between the Pt Schottky electrode and the ZnO nano-column film. The ZnO2 interface layer promotes surface passivation and suppresses the surface leakage current. This is expected to increase the Schottky barrier height to 0.78 eV. The H2O2 treated Schottky diode showed five orders of magnitude in current rectification between forward and reverse bias at 3 V.
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