Effect of Suspended Particles on the Drying Process of a Carrier-Fluid Droplet Sitting on a Solid Surface
We focus on an evaporation process of a volatile droplet on a temperature-controlled solid substrate. The process is strongly affected by suspending tiny particles inside the droplet, resulting in a well-known phenomenon called the coffee stain problem. The target systems in this study are (1) the water-hydrophilic particle and (2) the water-ethanol mixturehydrophilic particle. Spatio-temporal particle motion in the induced flow in the evaporation process is visualized by applying three-dimensional particle tracking velocimetry. The correlation between the particle behavior in the evaporation process and the morphological pattern of the droplet after dryout is also discussed.
particle droplet evaporation coffee stain problem particle behavior solutocapillary effect