  We consider electrodiffusion of ions in fluids, described by the
Nernst-Planck-Navier-Stokes system, in three dimensional bounded domains, with
mixed blocking (no-flux) and selective (Dirichlet) boundary conditions for the
ionic concentrations and Robin boundary conditions for the electric potential,
representing the presence of an electrical double layer. We prove global
existence of strong solutions for large initial data in the case of two
oppositely charged ionic species. The result hold unconditionally in the case
where fluid flow is described by the Stokes equations. In the case of
Navier-Stokes coupling, the result holds conditionally on Navier-Stokes
regularity. We use a simplified argument to also establish global regularity
for the case of purely blocking boundary conditions for the ionic
concentrations for two oppositely charged ionic species and also for more than
two species if the diffusivities are equal and the magnitudes of the valences
are also equal.
