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The effect of chemical modification of submicron barium titanate particles by the deposition of M x O y (x = Ti ,Co, Ni) oxide layers from aqueous solutions of the corresponding precursors is studied upon the surface properties of modified BaTiO3 particles and dielectric permittivity of organo inorganic compos ites obtained by their dispersion in the matrix of cyanoethyl ester of polyvinyl alcohol and useful in electrolu minescent light sources. It is shown that a significant increase (by about 25%) of the dielectric permittivity is observed only when adding Nb 2 O 5 , in comparison with a similar composite which contains unmodified BaTiO 3 . A correlation is found between the dielectric permittivity of the organo inorganic composites and the presence of Brensted neutral and basic centers with pK a = 6-13, localized on the surface of a filler, being capable of interacting with the polymer matrix. It is shown that an increase of the dielectric permittivity upon deposition of niobium oxide on the surface of BaTiO 3 is caused by formation of such centers and modification of the surface layer structure of BaTiO 3 particles, with transformation of rutile like Ti-O bonds to anatase like ones.

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