Electrokinetic microfluidic phenomena by a lattice Boltzmann model using a modified Poisson-Boltzmann equation with an excluded volume effect.
A lattice Boltzmann model (LBM) for electrokinetic microfluidics recently proposed by us [J. Colloid Interface Sci. 263, 144 (2003); Langmuir 19, 3041 (2003)] is employed by consideration of a modified Poisson-Boltzmann equation including an excluded volume effect. In our study, pressure is considered as the only external force for liquid flow. As commonly used, the Poisson-Boltzmann equation assumes only point charge, the predicted microfluidic phenomena of KCl and LiCl electrolyte solutions are theoretically the same; these phenomena, however, have been found to be experimentally different. Our LBM in conjunction with the modified Poisson-Boltzmann equation are capable of explaining this discrepancy and the results are in good agreement with recent experimental data for KCl and LiCl electrolyte solutions in pressure-driven microchannel flow, suggesting that our proposed LBM can be employed to predict the more complex microfluidic systems that might be problematic using conventional methods and electrokinetic models.
Nanoscale Technology and Engineering Laboratory, Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta T6G 2G8, Canada.
Baoming
B
Li
Daniel Y
DY
Kwok