10.1021/acs.langmuir.7b00946.s002
Andrea Fortini
Andrea
Fortini
Richard P. Sear
Richard P.
Sear
Stratification and Size Segregation of Ternary and
Polydisperse Colloidal Suspensions
during Drying
American Chemical Society
2017
power-law dependence
Size Segregation
film properties
Brownian dynamics simulations
ternary mixture
polydisperse spheres
particle size distribution
stratification morphologies
Polydisperse Colloidal Suspensions
bottom part
polydisperse mixtures
particle size
phoretic velocity
segregation effect
simulation show
2017-04-20 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Stratification_and_Size_Segregation_of_Ternary_and_Polydisperse_Colloidal_Suspensions_during_Drying/4960481
We
investigate the drying process of three-component and polydisperse
colloidal suspensions using Brownian dynamics simulations. We have
previously reported (<i>Phys. Rev. Lett</i>. <b>2016</b>, <i>116</i>, 118301) on the drying of binary mixtures.
For binary mixtures, we found that a gradient of colloidal osmotic
pressure develops during drying and that this leads to the final film
being stratified with a layer of smaller particles on top of a layer
of larger particles. Here, we find that stratification by size is
very general and also occurs in ternary and polydisperse mixtures.
We name the segregation effect colloidal diffusiophoresis. In particular,
we show that by changing the composition of a ternary mixture, different
stratification morphologies can be achieved and hence the film properties
can be tuned. In polydisperse spheres, colloidal diffusiophoresis
leads to enrichment in the large particles at the bottom part of the
film, whereas the top part is enriched with smaller particles. This
segregation means that in the final film, the particle size distribution
depends on height. Thus, the properties of the film will then depend
on height. We propose a model that predicts a power-law dependence
of the phoretic velocity on particle size. Results from the model
and simulation show a good agreement.