2016 年 49 巻 9 号 p. 845-849
A simplified electric field calculation is used to reveal several unique characteristics of the dielectrophoretic force to capture particles using electrodes on which conductive aligned micropillars are placed. This electrode configuration is a model to investigate a previous report about dielectrophoretic particle capture using an electrode on which carbon nanotubes have been synthesized. Conventionally, it has been believed that dielectrophoresis tends to capture larger particles because the dielectrophoretic force increases with increasing particle size when ordinal electrodes are used. However, when an electrode configuration with aligned conductive micropillars is used, small particles with diameters that are comparable to those of the micropillars can be selectively captured by dielectrophoresis. Accordingly, the size of the particles that need to be collected can be controlled by choosing an appropriate micropillar diameter. For relatively large particles, micropillars with a larger diameter can generate a stronger dielectrophoretic force over a larger area, such that a larger amount of particles can be collected. The number density of the micropillars was shown to negatively affect the dielectrophoretic force. The information obtained in this work will be useful for designing new DEP particle separators for size-selective particle capture. The use of controlled synthesis of CNTs is proposed to realize the fabrication of the electrode configuration modeled here.
