Control of Stratification in Drying Particle Suspensions via Temperature Gradients

dc.contributor.authorTang, Yanfeien
dc.contributor.authorGrest, Gary S.en
dc.contributor.authorCheng, Shengfengen
dc.contributor.departmentCenter for Soft Matter and Biological Physicsen
dc.contributor.departmentMacromolecules Innovation Instituteen
dc.date.accessioned2019-08-15T12:47:35Zen
dc.date.available2019-08-15T12:47:35Zen
dc.date.issued2019-03-26en
dc.description.abstractA potential strategy for controlling stratification in a drying suspension of bidisperse particles is studied using molecular dynamics simulations. When the suspension is maintained at a constant temperature during fast drying, it can exhibit "small-on-top" stratification with an accumulation (depletion) of smaller (larger) particles in the top region of the drying film, consistent with the prediction of current theories based on diffusiophoresis. However, when only the region near the substrate is thermalized at a constant temperature, a negative temperature gradient develops in the suspension because of evaporative cooling at the liquid-vapor interface. Since the associated thermophoresis is stronger for larger nanoparticles, a higher fraction of larger nanoparticles migrate to the top of the drying film at fast evaporation rates. As a result, stratification is converted to "large-on-top". Very strong small-on-top stratification can be produced with a positive thermal gradient in the drying suspension. Here, we explore a way to produce a positive thermal gradient by thermalizing the vapor at a temperature higher than that of the solvent. Possible experimental approaches to realize various thermal gradients in a suspension undergoing solvent evaporation and thus to produce different stratification states in the drying film are suggested.en
dc.description.notesPublic domain – authored by a U.S. government employeeen
dc.identifier.doihttps://doi.org/10.1021/acs.langmuir.8b03659en
dc.identifier.issn0743-7463en
dc.identifier.issue12en
dc.identifier.pmid30807180en
dc.identifier.urihttp://hdl.handle.net/10919/93143en
dc.identifier.volume35en
dc.language.isoenen
dc.rightsCreative Commons CC0 1.0 Universal Public Domain Dedicationen
dc.rights.urihttp://creativecommons.org/publicdomain/zero/1.0/en
dc.titleControl of Stratification in Drying Particle Suspensions via Temperature Gradientsen
dc.title.serialLangmuiren
dc.typeArticle - Refereeden
dc.type.dcmitypeTexten
dc.type.dcmitypeStillImageen

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