Superhydrophobic surface created by the silver mirror reaction and its drag-reduction effect on water

Stable superhydrophobic silver films were fabricated on glass substrates by using the silver mirror reaction. The water contact angle (CA) on the obtained silver surface was 154°, and a water droplet could easily roll off. Both the CA and surface roughness could be tailored by altering the initial silver ion concentration. The movement of a superhydrophobic ball on the surface of water was also investigated and compared with that of a superhydrophilic ball. The results suggested that the superhydrophobic coating on the ball repulsed water and provided extra supporting force, leading to a faster movement on the surface of water. We hope that our findings would improve the understanding of superhydrophobic properties and be useful in further research on drag-reducing materials.