Thermophoresis at a charged surface: the role of hydrodynamic slip

By matching boundary layer hydrodynamics with slippage to the force-free flow at larger distances, we obtain the thermophoretic mobility of charged particles as a function of the Navier slip length b. A moderate value of b augments Ruckenstein's result by a term 2b/lambda, where lambda is the Debye length. If b exceeds the particle size a, the enhancement coefficient a/lambda is independent of b but proportional to the particle size. Similar effects occur for transport driven by a salinity gradient or by an electric field.