Like-charge attraction and hydrodynamic interaction

We demonstrate that the attractive interaction measured between like-charged colloidal spheres near a wall can be accounted for by a nonequilibrium hydrodynamic effect. We present both analytical results and Brownian dynamics simulations which quantitatively capture the one-wall experiments of Larsen and Grier [Nature (London) 385, 230 (1997)], using a single unmeasured parameter.