(358e) Effects of Microtopography On Two-Dimensional Electrokinetic Patterning of Colloids On An Electrode Surface

Colloid self-assembly techniques are beneficial due to their ability to create organized architectures from a disordered suspension. Colloids have been used to enhance material properties including mechanical, heat transfer, or optical characteristics. There are inherent disadvantages of established colloid assembly techniques (solvent evaporation, sedimentation, and layer by layer deposition), namely the rate of assembly and the precision/resolution of the desired pattern. AC electrokinetic techniques, including rapid electrokinetic patterning (REP), have demonstrated rapid colloidal assembly and patterning.

This work explores the use of templates on an electrode surface to guide and retain colloids patterned on the electrode's surface. A parallel-plate electrode is used using two indium tin oxide (ITO) substrates (initial ITO thickness is approximately 500 nm). Simple micrometer geometries are etched into one ITO electrode. 1.0 micrometer particles are used to demonstrate the effect of microtopography on 2D colloidal patterning. A combination and balance of uniform and non-uniform electrokinetics, particle-particle interactions, and particle-electrode interactions result in improved colloidal pattern resolution.