Confined colloidal droplets dry to form circular mazes
arXiv:2502.19604
Abstract
During drying, particle-laden sessile droplets will leave so-called coffee-stain rings behind. This phenomenon is well-known and well-understood (Deegan et al., Nature 389, 827-829 (1997)). Here we show that when particle-laden droplets confined in a slit are allowed to evaporate very slowly, they do not deposit coffee rings, but form a surprisingly intricate, circular maze-like pattern. We present experiments that illustrate this pattern formation and discuss the factors that determine when such patterns can form. We are not aware of reports of natural examples of the formation of such beautiful patterns under confinement, although it seems likely that they exist.
Updated Supplementary Information: extra detail in Fig.S4 caption, extra detail for description of Figs. S4 and S5. Updated Author name spelling. Removed TEX formatting of reference in abstract