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Published February 13, 2009 | public
Journal Article

Dynamics of Concentrated Hard-Sphere Colloids Near a Wall

Abstract

We investigate the Brownian motion of hard-sphere colloids near a solid wall by Evanescent Wave Dynamic Light Scattering (EWDLS). We carried out measurements for various volume fractions of sterically stabilized poly(methyl methacrylate) (PMMA) particles over a range of scattering wave vectors, q. While in the dilute regime, the near wall short-time diffusion is significantly slowed down due to particle-wall hydrodynamic interactions (HI); as volume fraction increases, the wall effect is progressively diminished at all q's. We present a new analysis for the EWDLS short-time self- and collective diffusivities applicable to all volume fractions and a simple model for the self-diffusion describing the interplay between particle-wall and particle-particle HI. Moreover, a weaker decay of the near-wall self-diffusion coefficient with volume fraction is predicted by Stokesian dynamics simulations.

Additional Information

©2009 The American Physical Society. Received 19 July 2008; published 12 February 2009. We thank A. Schofield for providing the colloids and J. Dhont and P. Lang for discussions and a measurement in the Julich EWDLS setup (with the 154 nm sample). We acknowledge funding from GSRT (PENED-03E4566), NSF NIRT Grant No. (CBET 0506701) and EU Grants ''Cosines'' (MTCD-CT-2005-029944) and ''SoftComp'' (NMP3-CT-2004-502235). # 82.70.Dd Colloids # 47.57.-s Complex fluids and colloidal systems (fluid dynamics) # 68.35.Fx Diffusion; interface formation (solid surfaces) # 78.35.+c Brillouin and Rayleigh scattering; other light scattering (condensed matter)

Additional details

Created:
August 21, 2023
Modified:
October 18, 2023