Evaporation of colloidal droplets from aluminum-magnesium alloy surfaces after laser-texturing and mechanical processing

Abstract

Abstract Evaporation-induced self-assembly on solid surfaces is widely used for the production of photonic devices, circuit boards of electronic devices, and cooling technologies. There are numerous factors affecting self-assembly. However, the state of a solid surface is one of the most important. In this work, we analyzed the effect of mechanical processing methods (widely used in mechanical engineering) and promising pulsed laser texturing of aluminum-magnesium alloy on the characteristics of self-assembly of polystyrene (PS) particles during the evaporation of colloidal solution droplets. The patterns were visualized under a scanning electron microscope. The profile of an evaporating droplet was obtained using the optical shadow technique. It was found that during the evaporation of water droplets loaded with PS particles on aluminum-magnesium alloy samples, the ring-like patterns were formed. Such a pattern type was explained by the evaporation of a droplet in the constant contact diameter mode during almost the entire evaporation time (more than 90% of the total evaporation time). The dried patterns formed on aluminum-magnesium alloy surfaces after satin-finishing and laser texturing were found to be stretched parallel to the vector of laser beam or polishing tool movement due to capillary force. In addition, we determined the conditions when the particles formed spot-like patterns on laser-textured surfaces. These results provide new knowledge in understanding the effect of different processing methods of a material on the formation of dried patterns and are important for many applications.