Drag reduction of a miniature boat with superhydrophobic grille bottom

Water strider can slide on water surface with a very small drag force using its long superhydrophobic legs. Inspired by the water strider legs, we report here a novel design of superhydrophobic grille structure for drag reduction. A miniature boat covered with a superhydrophobic grille at the bottom is fabricated and compared with a normal boat with flat bottom in the same size, and a significant drag reduction is obtained by the former. Experiments also reveal that the grille structure exhibits a remarkable loading capacity supplied by the water surface tension. It is found that the optimal design of such a miniature boat with a considerable loading capacity and a small drag can be realized through controlling the length and the spacing of the grilles. This study shows a new idea to reduce the fluid drag in microfluidics, micro electromechanical system and other engineering areas.