Dynamic Contact Angles and Contact Angle Hysteresis on Laser-textured Aluminum Alloy Surfaces

In this work, we present experimental results of the dynamic characteristics (advancing and receding dynamic contact angles, contact angle hysteresis) of water droplet spreading over aluminum alloy surfaces modified by laser irradiation. Using equipment of the shadow images, we determined the geometrical dimensions of droplet spreading with rates of dosing of 10-600 mu l/min over the surfaces with an ordered texture. The texture was formed due to thermochemical processes during nanosecond laser processing of surfaces. Five textures, which differ by the crater-like arrangement, were created. The influence of the arrangement of the texture elements (relative to each other) on the dynamic characteristics of droplet spreading was found. It was shown that the contact angle hysteresis change depends on the type of formed texture, the droplet growth rate on the surface. Based on the comparison with polished surface, we showed that it is possible to control wetting and liquid spreading by creating the given texture on metal surfaces.