Date of Award
Master of Science (MS)
When a solid substrate is withdrawn from a liquid bath a thin coating is deposited whose thickness is given by the Landau-Levich-Derjaguin (LLD) law. We perform an experimental study of dip coating of particle suspensions showing that particles of a given size can become entrained in the meniscus by the competition between viscous and surface tension forces. This is called capillary filtration and can be used as a tunable dynamic filter. For single particle suspensions, filtration can be in terms of either clumps or single particles, with the relevant entrainment points depending upon the rheology of the working fluid, either Newtonian silicone oil or non-Newtonian shear-thinning xanthan gum solution. For bi-disperse suspensions, we show there is a range of capillary number where the smaller particle is entrained in the film and the larger particle remains in the fluid bath, thus filtering the particles by size.
Copeland, Connor, "Tunable Filtration of Particles During Dip-Coating" (2022). All Theses. 3911.