Dielectric properties of mesoporous sieves filled with NaNO₂

Studies of dielectric properties were carried out for MCM-41 molecular sieves whose pores were filled with NaNO₂ particles and whose pore sizes vary from 20 to 37 Å . The experimental data obtained were used to calculate the permittivity of confined particles on the base of a theoretical model for two-component composites with hexagonal structure and cylindrical inclusions. Additional NMR measurements confirmed that sodium nitrite in pores occurs in two coexistent modifications. A modification with high spin relaxation was suggested to respond for elevated conductivity of the samples under study. It was shown that the increase of the real part of permittivity is caused by the Maxwell-Wagner polarization.