  Thermo-osmotic and related thermo-phoretic phenomena can be found in many
situations from biology to colloid science, but the underlying molecular
mechanisms remain largely unexplored. Using molecular dynamics simulations, we
measured the thermo-osmosis coefficient by both mechano-caloric and
thermo-osmotic routes, for different solid-liquid interfacial energies. The
simulations reveal in particular the crucial role of nanoscale interfacial
hydrodynamics. For non-wetting surfaces , thermo-osmotic transport is largely
amplified by hydrodynamic slip at the interface. For wetting surfaces, the
position of the hydrodynamic shear plane plays a key role in determining the
amplitude and sign of the thermo-osmosis coefficient. Finally, we measure a
giant thermo-osmotic response of the water-graphene interface, which we relate
to the very low interfacial friction displayed by this system. These results
open new perspectives for the design of efficient functional interfaces for,
e.g., waste heat harvesting.
