  At finite Reynolds numbers particles migrate across flow streamlines to their
equilibrium positions in microchannels. Such a migration is attributed to an
inertial lift force, and it is well-known that the equilibrium location of
neutrally-buoyant particles is determined only by their size and the Reynolds
number. Here we demonstrate that the decoration of a bottom wall of the channel
by superhydrophobic grooves provides additional possibilities for manipulation
of neutrally-buoyant particles. It is shown that the effective anisotropic
hydrodynamic slip of such a bottom wall can be readily used to alter the
equilibrium positions of particles and to generate their motion transverse to
the pressure gradient. These results may guide the design of novel inertial
microfluidic devices for efficient sorting of neutrally-buoyant microparticles
by their size.
