下降(电信)
悬挂(拓扑)
流变学
化学工程
同种类的
动力学
基质(水族馆)
化学
材料科学
坐滴法
矿物学
热力学
复合材料
接触角
地质学
电信
海洋学
物理
数学
量子力学
同伦
计算机科学
纯数学
工程类
作者
S.M.M. Ramos,Damien Soubeyrand,Rémy Fulcrand,Catherine Barentin
出处
期刊:Langmuir
[American Chemical Society]
日期:2023-09-14
卷期号:39 (38): 13579-13587
标识
DOI:10.1021/acs.langmuir.3c01605
摘要
Drying of multicomponent sessile drops is a complex phenomenon involving intricate mechanisms. Here, we study the evaporation of drops made of paint suspension and investigate the influence of the substrate temperature and suspension concentration on the resulting deposit patterns. At low concentrations and temperatures, the pigments appear highly concentrated in a narrow area at the center of the drop, a morphology we call "fried eggs". Increasing the temperature or concentration leads to more homogeneous patterns. From a top-view camera used for monitoring the whole evaporative process, we identify three mechanisms responsible for the final pattern: inward/outward flows that convect the pigments, gelation of the paint suspension where pigments accumulate, and final drying of the drop that freezes the location of the pigments onto the substrate. The relative kinetics of these three mechanisms upon concentration and temperature govern the deposit growth and the morphology of the final pattern. These observations are quantitatively supported by rheological measurements highlighting a strong increase of the viscosity with concentration, consistent with the gelation mechanism. Finally, we show that the kinetics of drop drying is controlled by the substrate temperature.
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