Electrokinetic flow of non-Newtonian fluids in microchannels

CLAUDIO L. A. BERLI, MARÍA L. OLIVARES

JOURNAL OF COLLOID AND INTERFACE SCIENCE

Elsevier Science

Año: 2008 vol. 320 p. 582 - 589

0021-9797

A theoretical description of the electrokinetic flow of non-Newtonian fluids through slit and cylindrical microchannels is presented. Calculations are based on constitutive models of the fluid viscosity, and take into account wall depletion effects of colloids and polymer solutions. The resulting equations allow one to predict the flow rate and electric current as functions of the simultaneously applied electric potential and pressure gradients. It is found that (i) non-linear effects induced by the shear-dependent viscosity are limited to the pressure-driven component of the flow, and (ii) the reciprocity between electro-osmosis and streaming current is complied. Thus a generalized form of the force-flux relations is proposed, which is of interest in microfluidic applications. A theoretical description of the electrokinetic flow of non-Newtonian fluids through slit and cylindrical microchannels is presented. Calculations are based on constitutive models of the fluid viscosity, and take into account wall depletion effects of colloids and polymer solutions. The resulting equations allow one to predict the flow rate and electric current as functions of the simultaneously applied electric potential and pressure gradients. It is found that (i) non-linear effects induced by the shear-dependent viscosity are limited to the pressure-driven component of the flow, and (ii) the reciprocity between electro-osmosis and streaming current is complied. Thus a generalized form of the force-flux relations is proposed, which is of interest in microfluidic applications. A theoretical description of the electrokinetic flow of non-Newtonian fluids through slit and cylindrical microchannels is presented. Calculations are based on constitutive models of the fluid viscosity, and take into account wall depletion effects of colloids and polymer solutions. The resulting equations allow one to predict the flow rate and electric current as functions of the simultaneously applied electric potential and pressure gradients. It is found that (i) non-linear effects induced by the shear-dependent viscosity are limited to the pressure-driven component of the flow, and (ii) the reciprocity between electro-osmosis and streaming current is complied. Thus a generalized form of the force-flux relations is proposed, which is of interest in microfluidic applications.