By combining nano-scale surface roughening with a hydrophobic a-C:H:Si:O coating, we generated the super-hydrophobic surface with very low wetting angle hysteresis. We focused on the effect of the dual structure of the surface on the static and the dynamic wetting behaviours. It was observed that the dual rough surface is super-hydrophobic with a wetting angle around 160 degrees and a wetting angle hysteresis (difference between forwarding and receding angle) less than 5 degrees. On the other hand, mono rough surfaces in any scale appeared sticky and the wetting angle hysteresis ranged from 30 degrees to 60 degrees depending on the dimension of the surface roughness. (c) 2007 Elsevier B.V. All rights reserved.