An electrophoretic technique is provided for moving a plurality of chemicals into distinct zones for immobilization on a solid surface. The technique includes introducing a first electrolyte and a second electrolyte into a channel, and interposing between the first and second electrolytes at least one solution containing a plurality of chemicals. Under a given electric field, the first electrolyte has anions with higher effective mobility than the chemicals and the second electrolyte has anions with lower effective mobility than the chemicals. When an electrical potential is applied across the length of the channel the plurality of chemicals in the solution are moved into spatial zones. The chemicals in the zones can then be bound to the interior surface of the channel. Chemicals so bound to the wall surface can be used to build very small structures such as arrays and electrical conducting structures.