Short-time self-diffusion of nearly hard spheres at an oil-water interface

Y. Peng, W. Chen, Th M. Fischer, D. A. Weitz, Penger Tong

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Optical microscopy and multi-particle tracking are used to study hydrodynamic interactions of monodisperse polymethylmethacrylate (PMMA) spheres at a decalin-water interface. The short-time self-diffusion coefficient measured at low surface coverage has the form DSS(n) = α D0(1 - β n), where n is the area fraction occupied by the particles, and D0 is the Stokes-Einstein diffusion coefficient in the bulk suspension of PMMA spheres in decalin. The measured values of α are found to be in good agreement with the numerical calculation for the drag coefficient of interfacial particles. The measured values of β differ from that obtained for bulk suspensions, indicating that hydrodynamic interactions between the particles have interesting new features at the interface.

Original languageEnglish (US)
Pages (from-to)243-261
Number of pages19
JournalJournal of Fluid Mechanics
StatePublished - 2009
Externally publishedYes

Bibliographical note

Funding Information:
We have benefited from illuminating discussions and correspondence with H. Stone, M. Brenner, A. Schofield, B. Ackerson, T. Squires and A. Levine. PT was supported by the Research Grants Council of Hong Kong SAR under grant no. HKUST603305. TMF acknowledges support from the US National Science Foundation (NSF) under CHE-0649427, and DAW acknowledges NSF for support under DMR-0602684.


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