Theoretical investigation regarding the hindered behavior of colloidal suspensions of nonuniformly charged nanoparticles in microfluidic devices

Abstract

A dilute colloidal suspension confined in a slit channel, where the dispersed nanoparticles are nortuniformly charged, is considered. Long-range interactions due to the electrostatic potential are analyzed under the Debye-Huckel theory. The hindered behavior with respect to concentration partitioning and hindered diffusion have been examined intensively as a function of total charge, as well as the dipole moment of the nanocolloid in a variety of physicochemical situations. It was found that the dipole moment of the particles obviously enhances partitioning into the channel, whereas the total charge either enhances or restrains the partitioning depending upon the sign of the electric charge. Competition between repulsive and attractive particle-wall interactions provide the localized density distributions of nanocolloids and also crossovers in the hindered diffusion coefficient.