Chemical composition and barrier properties of Ag nanoparticle-containing sol-gel films in oxidizing and reducing low-temperature plasmas

Silver nanoparticle-containing silica sol-gel coatings were synthesised using tetraethylorthosilicate (TEOS), HNO3 and AgNO3 as the main precursors and 3-(2-aminoethylamino)propyl trimethoxysilane (DIAMO) as a stabiliser. The stability and the barrier properties of the coatings were studied by means of UV/Vis spectroscopy, FTIR reflection absorption spectroscopy (IRRAS), spectroscopic Ellipsometry and electrochemical impedance spectroscopy (EIS). Both the long-term stability and barrier properties of the coatings could be tailored by lowtemperature O-2 and H-2-plasma treatments. The oxidative plasma treatment enabled the change of the matrix from organic-inorganic to silica-like and the reductive treatment led to a reduction of the formed passive film on the Ag nanoparticles within the matrix. Thereby, based on the combination of sol-gel chemistry with subsequent plasma treatment new thin film functionalities can be achieved. (C) 2007 Elsevier B.V. All rights reserved.