Relaxation Dynamics of Colloidal Particles at Liquid Interfaces
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CitationWang, Anna, David M. Kaz, Ryan McGorty, and Vinothan N. Manoharan. 2013. Relaxation Dynamics of Colloidal Particles at Liquid Interfaces. In Proceedings of the 4th International Symposium on Slow Dynamics in Complex Systems (AIP), Sendai, Japan, December 2-7, 2012, AIP Conf. Proc. 1518: 336-343. doi: 10.1063/1.4794594
AbstractWe study the dynamics of colloidal particles as they approach and breach a water-oil interface. We use a fast 3D imaging technique, digital holographic microscopy, to track particles with 2 nm precision and sub-millisecond time resolution. We find that polystyrene particles dispersed in water or water-glycerol mixtures relax logarithmically with time after breaching the interface and do not reach equilibrium on experimental timescales. By contrast, decane-dispersed PMMA particles show fast dynamics and reach a steady-state height within milliseconds. We attribute the difference to the surface properties of the particles. We also probe the dependence of the relaxation rate on surface charge by studying carboxyl-functionalized particles under varying acid concentrations. We conclude that the slow relaxation may be due to contact-line pinning on topographical defects rather than surface charges.
Citable link to this pagehttp://nrs.harvard.edu/urn-3:HUL.InstRepos:24902730
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