Issue
EPL
Volume 84, Number 2, October 2008
Article Number 28003
Number of page(s) 6
Section Interdisciplinary Physics and Related Areas of Science and Technology
DOI http://dx.doi.org/10.1209/0295-5075/84/28003
Published online 07 October 2008
EPL, 84 (2008) 28003
DOI: 10.1209/0295-5075/84/28003

Short-time self-diffusion of weakly charged silica spheres at aqueous interfaces

Wei Chen and Penger Tong

Department of Physics, Hong Kong University of Science and Technology - Clear Water Bay, Kowloon, Hong Kong

penger@ust.hk

received 7 April 2008; accepted in final form 9 September 2008; published October 2008
published online 7 October 2008

Abstract
Optical microscopy and multi-particle tracking are used to study the short-time self-diffusion of weakly charged silica spheres at a water-air interface. The measured short-time self-diffusion coefficient DSS has the form, DSS/D0=$\alpha$ (1-$\beta$ n), where n is the area fraction occupied by the particles and D0 is the Stokes-Einstein diffusion coefficient of individual particles in the bulk fluid. The obtained values of $\alpha$ and $\beta$ differ from those obtained for bulk suspensions, indicating that hydrodynamic interactions between the interfacial particles have interesting new features when compared with their three-dimensional counterpart.

PACS
82.70.Dd - Colloids.
68.05.Gh - Interfacial properties of microemulsions.
05.40.-a - Fluctuation phenomena, random processes, noise, and Brownian motion.

© EPLA 2008