Fluid–fluid equilibrium of a mixture of non-polar and dipolar hard spheres in an applied field

Abstract

The influence of an external static electric field on the high-pressure fluid–fluid equilibrium of a mixture of non-polar and dipolar hard-sphere molecules has been investigated by a generalization of the thermodynamic perturbation theory of mixtures of polar fluids. The effect of the field was considered via the field-dependent relative permittivity. It was found that the critical temperature at a fixed pressure increases with the field strength. This increase is more rapid at lower pressures. At low pressures the coexisting phases are richer in the dipolar component and therefore the effect of the field is stronger. The behaviour of the critical loci changes in the presence of the field.