We perform extensive boundary driven non-equilibrium molecular dynamics (NEMD) simulations of model biphasic binary liquid-liquid mixtures with Lennard-Jones potentials. Temperature gradients are imposed along the interfaces. We investigate how the Soret coefficient is modified in their vicinity compared to the bulk liquid. The segregation of both components weakens when approaching the Gibbs dividing surface. Approximate bulk Soret behavior is reached at about 5 nm (15 particle diameters) from the interface. The local densities in the non-equilibrium system are compared with those found in equilibrium interfacial systems at the corresponding temperatures. (C) 2011 Elsevier B.V. All rights reserved.