The micrometer-scaled channels with different width and depth on the Si surface were prepared by pulse laser ablation. Effect of topography on wettability of the laser-ablated Si surface was discussed by investigation of water contact angle (WCA). The results indicate that WCA was decreased with increasing the width of the channels when the depth of the channels on the Si surface was certain, and increased with increasing the depth of the channels when the width of the channels on the Si surface was certain. The maximum WCA of the laser-ablated Si surface is 165°, corresponding to size of the square-shaped posts, ablated width and depth being 13×13, 4 and 10 (m, respectively. In addition, the micrometer-scaled tips on the laser-ablated Si surface obviously affect its wettability. Accordingly, the certain-extent-controllable wettability of solid surface can be prepared by laser ablation.

Key words: laser ablation, wettability, Si surface