Shape Changes of Colloidal Suspension Droplets during Drying

Simple analytical model of capillary flow in an evaporating sessile drop

“…To satisfy the anchoring condition, a flow of liquid has to occur inside the drop. An outward flow in a drying drop is produced when the contact line is pinned so that liquid that is removed by evaporation from the edge of the drop must be replenished by a flow of liquid from the interior [1,2,3]. This flow is capable of transferring 100% of the solute to the contact line and thus accounts for the strong perimeter concentration of many stains.…”

“…The models [1] and [3] deal with the vertically averaged radial flow of the fluid. The next Section describes how to obtain the space distribution of the fluid flow.…”

Using convective flow splitting for the direct printing of fine copper lines

“…It has recently been reported that evaporating droplets containing passive flow markers like polystyrene spheres produce distinct ring stain patterns at the drop periphery [12][13][14][15][16][17] caused by contact line pinning. Numerical [18][19][20] and experimental studies [21][22][23] of small and highly volatile droplets like chloroform evaporating in air at room temperature have also shown that evaporative cooling creates Bénard-Marangoni 11 ͑i.e., surface tension dominated͒ convection patterns above the critical Marangoni number.…”

Droplet Behaviors on Substrates in Thin-Film Formation Using Ink-Jet Printing

“…Ring-like deposits have been reported: Bediwi and coworkers (19) reported on the difficulties of obtaining a uniform deposit, Parisse and coworkers (20) investigated the deformation of sessile drops that was due to a sol-gel transition of the solute at the boundary, and Adachi and coworkers (21) studied the stick-slip motion of the contact line of colloidal liquids and found that ridges and a striped pattern form as a dilute suspension dries on a surface, Conway and coworkers (22) measured the effect of ring formation on the evaporation rate of sessile droplets and found that coffee stains occur when the initial concentration of polystyrene spheres was greater than 8%, Denkov and coworkers (23) found that static electricity causes the ordering of micrometer-size polystyrene latex spheres when the thickness of the water layer containing particles becomes approximately equal to the particle diameter, Fanton and coworkers (24) researched the phenomena that the Marangoni convection causes star-like accumulation of solute near the contact line, Yang (25) described that temperature difference between droplet and substrate causes many types of droplet profiles during evaporation.…”