  We present an extension to the Poisson-Boltzmann model where the dipolar
features of solvent molecules are taken explicitly into account. The
formulation is derived at mean-field level and can be extended to any order in
a systematic expansion. It is applied to a two-plate system with oppositely
charged surfaces. The ion distribution and profiles in the dipolar order
parameter are calculated and can result in a large correction to the
inter-plate pressure.
