Effect of micro-groove size on the hydrophobicity of aluminum surface

In this paper, the micro-groove structure is designed on the surface of aluminum alloy by high speed wire cutting discharge machine (HS-WEDM). A multi-scale surface with micro structure was fabricated by this method. The paper design a series different groove spacing, groove depth and groove width and orthogonal design was using to analyze the relationship between the size of micro structure and the wettability of materials. The results show that the effect of the groove width on surface wettability is maximum, When the the groove spacing is 300μm, the groove depth is 100μm and the width of the groove is 230μm, the contact angle of the material surface is maximum, which is 155.98°. After observing the surface, it is can be known that the existence of groove structure can reduce the droplet and solid surface contact area greatly. In addition, these grooves sealed a plenty of air to increase the contact area of the droplet and the air that the solid surface are difficult to be wetted by droplets. It is feasible that realizing the change of the surface wettability by using optical combination.