Capillary Sorting of Particles by Dip Coating
Name
PhysRevApplied.12.011001.pdf
Description
Published version
Size
717.94 KB
Format
Adobe PDF
Checksum (MD5)
5bd2996046deba847d1284994776e170
Author(s)
Dincau, BM
Bazant, Martin Z
Dressaire, Emilie
Sauret, Alban
Date Issued
July 2019
Journal
Physical Review Applied
Publisher
American Physical Society (APS)
Citation
Dincau, BM, Bazant, Martin Z, Dressaire, E and Sauret, A. 2019. "Capillary Sorting of Particles by Dip Coating." Physical Review Applied, 12 (1).
Version
Final published version
Abstract
In this letter, we describe the capillary sorting of particles by size based on dip coating. A substrate withdrawn from a liquid bath entrains a coating whose thickness depends on the withdrawal speed and the liquid properties. If the coating material contains particles, they will only be entrained when the viscous force pulling them with the substrate overcomes the opposing capillary force at the deformable meniscus. This force threshold occurs at different liquid thicknesses for particles of different sizes. Here, we show that this difference can be used to separate small particles from a mixed suspension through capillary filtration. In a bidisperse suspension, we observe three distinct filtration regimes. At low capillary numbers, Ca, no particles are entrained in the liquid coating. At high Ca, all particle sizes are entrained. For a range of capillary numbers between these two extremes, only the smallest particles are entrained while the larger ones remain in the reservoir. We explain how this technique can be applied to polydisperse suspension. We also provide an estimate of the range of capillary number to separate particles of given sizes. The combination of this technique with the scalability and robustness of dip coating makes it a promising candidate for high-throughput separation or purification of industrial and biomedical suspensions.
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
Massachusetts Institute of Technology. Department of Mathematics
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DOI of Published Version
https://doi.org/10.1103/physrevapplied.12.011001
