TY - JOUR
T1 - Stratification Dynamics in Drying Colloidal Mixtures
AU - Howard, Michael P.
AU - Nikoubashman, Arash
AU - Panagiotopoulos, Athanassios Z.
N1 - Funding Information:
We gratefully acknowledge use of computational resources supported by the Princeton Institute for Computational Science and Engineering (PICSciE) and the Office of Information and Technology’s High Performance Computing Center and Visualization Laboratory at Princeton University. Financial support for this work was provided by the Princeton Center for Complex Materials (PCCM), a U.S. National Science Foundation Materials Research Science and Engineering Center (grant DMR-1420541). Additionally, M.P.H. received Government support under Contract FA9550-11-C-0028 and awarded by the Department of Defense, Air Force Office of Scientific Research, National Defense Science and Engineering Graduate (NDSEG) Fellowship, 32 FR 168a, and the Blue Waters sustained-petascale computing project, which is supported by the National Science Foundation (Awards OCI-0725070 and ACI-1238993) and the state of Illinois. Blue Waters is a joint effort of the University of Illinois at Urbana−Champaign and its National Center for Supercomputing Applications. A.N. received support from the German Research Foundation (DFG) under Project NI 1487/2-1.
Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/4/18
Y1 - 2017/4/18
N2 - Stratification in binary colloidal mixtures was investigated using implicit-solvent molecular dynamics simulations. For large particle size ratios and film Péclet numbers greater than unity, smaller colloids migrated to the top of the film, while big colloids were pushed to the bottom, creating an "inverted" stratification. This peculiar behavior was observed in recent simulations and experiments conducted by Fortini et al. [Phys. Rev. Lett. 2016, 116, 118301]. To rationalize this behavior, particle size ratios and drying rates spanning qualitatively different Péclet number regimes were systematically studied, and the dynamics of the inverted stratification were quantified in detail. The stratified layer of small colloids was found to grow faster and to larger thicknesses for larger size ratios. Interestingly, inverted stratification was observed even at moderate drying rates where the film Péclet numbers were comparable to unity, but the thickness of the stratified layer decreased. A model based on dynamical density functional theory is proposed to explain the observed phenomena.
AB - Stratification in binary colloidal mixtures was investigated using implicit-solvent molecular dynamics simulations. For large particle size ratios and film Péclet numbers greater than unity, smaller colloids migrated to the top of the film, while big colloids were pushed to the bottom, creating an "inverted" stratification. This peculiar behavior was observed in recent simulations and experiments conducted by Fortini et al. [Phys. Rev. Lett. 2016, 116, 118301]. To rationalize this behavior, particle size ratios and drying rates spanning qualitatively different Péclet number regimes were systematically studied, and the dynamics of the inverted stratification were quantified in detail. The stratified layer of small colloids was found to grow faster and to larger thicknesses for larger size ratios. Interestingly, inverted stratification was observed even at moderate drying rates where the film Péclet numbers were comparable to unity, but the thickness of the stratified layer decreased. A model based on dynamical density functional theory is proposed to explain the observed phenomena.
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U2 - 10.1021/acs.langmuir.7b00543
DO - 10.1021/acs.langmuir.7b00543
M3 - Article
C2 - 28349690
AN - SCOPUS:85018516957
SN - 0743-7463
VL - 33
SP - 3685
EP - 3693
JO - Langmuir
JF - Langmuir
IS - 15
ER -