Cross-sectional capacitance measurement of particle concentration in a microchannel with multi-layered electrodes

In the present study, cross-sectional capacitance is measured in a microchannel with 12 multi-layered electrodes. The cross-sectional capacitances of microparticles of three different diameters are measured upstream and downstream. Based on these measurements, the particle concentration in terms of particle volume fraction is calculated. The particle volume fractions at three configuration areas of electrode pairs, namely, at ones containing adjacent, horizontal, and vertical pairs, are considered for ease of understanding of the particle concentration for different electrode pairs. The particle volume fraction shows an increment of 1.0-9.3% for electrode pairs near the channel walls, but decreased by 0.4-0.96% for center electrode pairs from the upstream cross-section to the downstream cross-section. Moving from the inlets to the outlet, the particles drift away from the center of the microchannel and approach the channel walls and the number of particles that migrate toward the channel walls increases clearly in the outlet area. (C) 2013 Elsevier Ltd. All rights reserved.