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P. Obreja, D. Cristea, M. Purica, R. Gavrila, F. Comanescu

Polymers doped with metal oxide nanoparticles with controlled refractive index (in English)

Polimery 2007, No 9, 679


Summary

Polymer nanocomposites for optical applications, with controlled refractive index in the range 1.46-1.78 were prepared by chemical route and sol-gel process, starting from poly(methylmethacrylate) (PMMA), hydroxyethylmethacrylate (HEMA), polyvinyl alcohols (PVA-1 and PVA-2) and metal oxides from alkoxides or inorganic compounds. The properties of these materials modified by metal oxide nanoparticles depend on the composition, metal oxide concentration, particle size and dispersion homogeneity. Ellipsometric method was used to analyse the changes in the refractive index of the nanocomposites with respect to increasing particle concentration and the spectrophotometry to determine the optical transmittance. The size and dispersity of the nanoparticles in the polymer matrix were evaluated using atomic force microscopy (AFM). As expected, the refractive index of the polymer thin films, spin coated onto substrates, increases with increasing oxide concentration for the polymers modified with TiO2, ZrO2 or CuO in the entire visible region and decreases with increasing oxide concentration when the polymers are modified with SiO2. For the all compounds the transmittance remains above 90% in the visible wavelength spectra. The particle dimensions are in the range 10-70nm and were controlled through the method and the parameters of syntheses.


Key words: polymer nanocomposites, refractive index, transmittance, particle size, atomic force microscopy


e-mail: paulao@imt.ro


P. Obreja, D. Cristea, M. Purica, R. Gavrila, F. Comanescu

Polymers doped with metal oxide nanoparticles with controlled refractive index (in English)