We present a continuum-level description of dynamics of a thin electrolyte film on substrate which is characterized by spatially periodic variation of surface properties.The model couples together the electrostatic effects and viscous flow in the liquid. Linear stability analysis is carried out using a combination of numerical techniques for finding the eigenvalues of the discretized stability problem, asymptotic methods valid for small charge density variation, and Floquet theory. Substrate non-uniformity can have either stabilizing or destabilizing effect. For the important practical case of a liquid film with oppositely charged boundaries and thickness comparable to the Debye length, transition from stabilizing to destabilizing influence is observed as the patterning wavelength is decreased. Numerical simulations of the strongly nonlinear evolution of the film are conducted, with emphasis on competition between patterns induced by substrate nonuniformity and by the intrinsic nonlinearity present even for uniform substrate. The topic of motion of contact line over patterned surface will also be discussed briefly. (Joint work with M. Jutley.)