Colloidal Monolayer Trapped near a Charged Wall: A Synchrotron X-Ray Diffraction Study

D. K. Satapathy, O. Bunk, K. Jefimovs, K. Nygård, H. Guo, A. Diaz, E. Perret, F. Pfeiffer, C. David, G. H. Wegdam, J. F. van der Veen
2008 Physical Review Letters  
Using x-ray diffraction from microfluidic channel arrays, we have determined concentration profiles of charge-stabilized silica colloids (radius 60 AE 2 nm) 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.
doi:10.1103/physrevlett.101.136103 pmid:18851466 fatcat:afplku3wjnax7auunbyiiw6kzq