title: A new method of evaluating the average electro-osmotic velocity in microchannels.
abstract: A new and simple method to evaluate the average electro-osmotic flow velocity in microchannels is presented in this paper. In this method, the average electro-osmotic flow velocity is determined by using the slope of the measured current-time relationship during the electro-osmotic flow of one solution replacing another similar solution. The two solutions have the same electrolyte and a small difference in ionic concentration. Careful experiments were conducted to measure the electrical current change with time during such a displacing process under a constant applied electrical field. KCl and LaCl3 electrolyte solutions and 10-cm-long polyamide-coated silica capillary tubes of 100 and 200 microm in internal diameter were used in this study. The average velocities were determined by using the slope method. A numerical model was also developed to predict the average velocity of such an electro-osmotic flow. An excellent agreement in the average velocities between the slope method and the model predictions was found.
authors.affiliation: Department of Mechanical & Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario, M5S 3G8, Canada.
authors.forename: Liqing
authors.initials: L
authors.lastname: Ren
authors.forename: Carlos
authors.initials: C
authors.lastname: Escobedo-Canseco
authors.forename: Dongqing
authors.initials: D
authors.lastname: Li