Molecular and continuum boundary conditions for a miscible binary fluid - art. no. 178302

We show that molecular-dynamics simulations can furnish useful boundary con ditions at a solid surface bounding a two-component fluid. In contrast to s ome previous reports, convective-diffusive flow is consistent with continuu m equations down to atomic scales. However, concentration gradients can pro duce flow without viscous dissipation that is inconsistent with the commonl y used Navier slip condition. Also, differential wetting of the two compone nts coupled to a concentration gradient can drive convective flows that cou ld be used to make nanopumps or motors.