Abstract
Using x-ray diffraction from microfluidic channel arrays, we have determined concentration profiles of charge-stabilized silica colloids (radius ) confined between two like-charged dielectric walls at a few hundred nanometer distance. In solutions of very low ionic strength, strongly repulsive Coulomb interactions drive the colloids toward the central region between the walls. The addition of a small quantity of salt ions (0.2 mM) causes a dense colloidal monolayer to be trapped near the walls.
- Received 26 June 2008
DOI:https://doi.org/10.1103/PhysRevLett.101.136103
©2008 American Physical Society
Synopsis
Imaging colloids
Published 29 September 2008
High-intensity x-ray measurements show how suspended particles in a narrow channel are attracted to—or repelled from—the channel walls depending on the ionic concentration of the suspension. These results could have implications for the design of nanofluidic devices.
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