  The classical fluid dynamics boundary condition of no-slip suggests that
variation in the wettability of a solid should not affect the flow of an
adjacent liquid. However experiments and molecular dynamics simulations
indicate that this is not the case. In this paper we show how flow over a solid
substrate with variations of wettability can be described in a continuum
framework using the interface formation theory developed earlier. Results
demonstrate that a shear flow over a perfectly flat solid surface is disturbed
by a change in its wettability, i.e. by a change in the chemistry of the solid
substrate. The magnitude of the effect is shown to be proportional to
cos(t1)-cos(t2) where t1 and t2 are the equilibrium contact angles that a
liquid-gas free surface would form with the two chemically different parts of
the solid surface.
