  We consider the influence of electric field gradients on the phase behavior
of nonpolar binary mixtures. Small fields give rise to smooth composition
profiles, whereas large enough fields lead to a phase-separation transition.
The critical field for demixing as well as the equilibrium phase separation
interface are given as a function of the various system parameters. We show how
the phase diagram in the temperature-composition plane is affected by electric
fields, assuming a linear or nonlinear constitutive relations for the
dielectric constant. Finally, we discuss the unusual case where the interface
appears far from any bounding surface.
