| Popis: |
This study develops a technique to control the timing, spacing (interval), and velocity of particles in a microchannel flow by periodically exerting forces on the particles over space and time. The periodic force was produced by dielectrophoretic force using boxcar-shaped electrodes on the channel wall. We could define the timing, interval, and velocity of the particles by configuring the on–off cycles of the applied voltage. Controlling the particle spacing and timing when it crosses a position in the channel and the focusing effect in the cross-sectional position could improve the performance and throughput of microfluidics, particularly for sensing, active sorting, and encapsulation of particles and cells. The proposed technique was first evaluated by a one-dimensional analysis based on a perturbation theory. We conducted a numerical simulation to solve the dielectrophoretic force distribution and the equation of motion of the particles to understand the relationship between the force and the particle motion in the boxcar-electrode region. We measured the velocity and position of the micro-particles flowing over the boxcar-electrode region in the microchannel and demonstrated the performance and accuracy of the proposed technique for alignment and timing control. The probability density functions (PDFs) of the period between the particles, particle velocity, and timing, concentrated at the target value with minimal variation. Furthermore, the measurement of particles with diameters of 8, 10, and 12 μm resulted in the same PDFs, which showed the applicability to a reasonable variation of particle diameters. |
Full text from SpringerLink