Colloidal electrostatic interactions near a conducting surface.
Like-charged colloidal spheres dispersed in de-ionized water are supposed to repel each other. Instead, artifact-corrected video microscopy measurements reveal an anomalous long-ranged like-charge attraction in the interparticle pair potential when the spheres are confined to a layer by even a single-charged glass surface. These attractions can be masked by electrostatic repulsions at low ionic strengths. Coating the bounding surfaces with a conducting gold layer suppresses the attraction. These observations suggest a possible mechanism for the anomalous confinement-induced attractions.
Polin
Marco
M
Center for Soft Matter Research, New York University, 4 Washington Place, New York, New York 10003, USA.
Grier
David G
DG
Han
Yilong
Y