Dielectric Properties of Multilayer Optically Transparent TiO2-Nanosilver Coating on Polyester Substrate Obtained by Solvent Method

Resumo

Thin functional, optically active TiO₂, TiO₂/Ag, and TiO₂/Ag/TiO₂ films on a polyethylene terephthalate substrate were obtained by a layer-by-layer deposition method from colloidal solutions. The filmforming TiO₂ sol was obtained by the sol-gel method. The silver coating was deposited from an aqueous solution of silver nitrate followed by its photolysis in a film. The physicochemical and dielectric properties of the obtained coatings were studied in terms of the number and order of alternation of the deposited layers. It was found that the dielectric spectrum of TiO₂, TiO₂/Ag, and TiO₂/Ag/TiO₂ films was similar to the dielectric characteristic of ceramic samples of titania in anatase and rutile phases and characterized by the presence of a relaxation maximum. The maximum position and its intensity depended on the type of alternating layers of the film and the frequency and on the magnitude of the measuring voltage, respectively.