2014/12/04 by C. Nadir Kaplan, Kaplan, C. Nadir, Ning Wu +7 · 1 citation
Engineering · #FOS: Physical sciences #Fluid Dynamics and Thin Films #Materials Science (cond-mat.mtrl-sci) #Nanomaterials and Printing Technologies #Soft Condensed Matter (cond-mat.soft)
paper · pdf · doi:10.48550/arxiv.1412.1813
openalex publication_date 2014/12/04 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Drying suspensions often leave behind complex patterns of particulates, as might be seen in the coffee stains on a table. Here we consider the dynamics of periodic band or uniform solid film formation on a vertical plate suspended partially in a drying colloidal solution. Direct observations allow us to visualize the dynamics of the band and film deposition, and the transition in between when the colloidal concentration is varied. A minimal theory of the liquid meniscus motion along the plate reveals the dynamics of the banding and its transition to the filming as a function of the ratio of deposition and evaporation rates. We also provide a complementary multiphase model of colloids dissolved in the liquid, which couples the inhomogeneous evaporation at the evolving meniscus to the fluid and particulate flows and the transition from a dilute suspension to a porous plug. This allows us to determine the concentration dependence of the bandwidth and the deposition rate. Together, our findings allow for the control of drying-induced patterning as a function of the colloidal concentration and evaporation rate.