Nanoparticle-Induced Gelation of Bimodal Slurries with Highly Size-Asymmetric Particles : Effect of Surface Chemistry and Concentration

A systematic study has been performed to investigate the effect of surface potential of nanoparticles on the rheological behavior of bimodal suspensions, using a model system consisting of polystyrene latex (primary size ∼530 nm) and alumina-coated silica (primary size ∼12 nm) particles. The surface...

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Veröffentlicht in:Langmuir : the ACS journal of surfaces and colloids. - 1992. - 31(2015), 51 vom: 29. Dez., Seite 13639-46
1. Verfasser: Lee, Jooyoung (VerfasserIn)
Weitere Verfasser: Lee, Seong Jae, Ahn, Kyung Hyun, Lee, Seung Jong
Format: Online-Aufsatz
Sprache:English
Veröffentlicht: 2015
Zugriff auf das übergeordnete Werk:Langmuir : the ACS journal of surfaces and colloids
Schlagworte:Journal Article
Beschreibung
Zusammenfassung:A systematic study has been performed to investigate the effect of surface potential of nanoparticles on the rheological behavior of bimodal suspensions, using a model system consisting of polystyrene latex (primary size ∼530 nm) and alumina-coated silica (primary size ∼12 nm) particles. The surface potential of small particles was tuned by varying the solution pH, causing them to be repulsive to each other, attractive to each other, and oppositely charged to the large particles, while the large particles remained electrostatically stabilized. We found that the rheological properties could be dramatically changed from viscous to gel-like depending on the surface potential and concentration of small particles. A colloidal gel was induced by small particles when the small particles had the opposite charge to the large particles and a volume fraction of 10(-4) < ϕsmall < 10(-3), and when the small particles were attractive to each other above a critical threshold, ϕsmall > 10(-4). Cryo-SEM distinguished the gel structures to be either short bridging gels produced by oppositely charged small particles or long bridging gels or dense gels produced by attractive small particles. On the basis of this rheological behavior and microstructure, we prepared a phase diagram of highly size-asymmetric bimodal colloids with respect to the surface chemistry and concentration of small particles
Beschreibung:Date Completed 20.04.2016
Date Revised 29.12.2015
published: Print-Electronic
Citation Status PubMed-not-MEDLINE
ISSN:1520-5827
DOI:10.1021/acs.langmuir.5b03752