Microprism using capillary alignment

Abstract

When a microstructure is placed on a droplet, the structure is positioned and remains at a particular position due to capillary forces. By using this phenomenon, two-dimensional arrangements on droplets have been widely developed. In this study, we fabricate a three-dimensional structure (prism shape) by placing two circular plates on a droplet. The paper explains the dynamics of the positioning both experimentally and numerically. Through experiment and simulation, we found that the rotational positioning is determined by surface tension and the two plates are supported by internal pressure and surface tension. The apex angle of the prism can be easily tuned by changing its volume. As described at the end of the paper, a prism composed of a droplet of silicone oil and two transparent circular SU-8 plates is encapsulated by depositing an organic Parylene membrane. The shape of the liquid is fixed, and a non-evaporative and non-deformable prism is formed with a volume of less than 1 mm3. © 2011 IOP Publishing Ltd.