Directed Self-Assembly of Spherical Particles on Patterned Electrodes by an Applied Electric Field

by A. Winkleman et al. Advanced Materials, 7 Jun 2005 Assembly techniques can produce patterns that would otherwise be difficult to make, but self-assembly processes can lack flexibility in the designs that can be produced. Our approach takes advantage of electrostatic forces to provide highly flexible patterns of glass microspheres. Patterns ranging from highly ordered arrays to arbitrary designs can be made, and in contrast to other such assembly techniques, it doesn't need to be carried out in solution. A polystyrene substrate is coated with layers of gold and chromium, which are then patterned with a self-assembled monolayer using microcontact printing. The areas of metal not protected by the monolayer are then etched to reveal windows of the substrate. When a high voltage is applied to the gold and the surface is flooded with glass microspheres, electrostatic forces ensure that one microsphere remains in each window, whilst tapping of the substrate minimizes defects. As this method doesn't rely on an assembly process between the microspheres, any pattern can be generated. Read more