Patterned Colloidal Deposition Controlled by Electrostatic and Capillary Forces

We use substrates chemically micro-patterned with anionic and cationic regions to govern the deposition of charged colloidal particles. The direct observation of colloidal assembly suggests that this process include two steps, an initial patterned attachment of colloids to the substrate due to screened electrostatic interactions and an additional ordering of the structure driven by lateral capillary forces. This approach makes it possible to fabricate high-resolution two-dimensional arrays of colloidal particles.