Abstract
A new technique for measuring ion velocity and diffusivity in the vicinity of a microchannel wall was proposed to investigate the ion diffusive phenomena. The technique employs the caged fluorescent dye and the evanescent wave illumination. The velocities and diffusivities in the vicinity of the wall were compared with those in the bulk flow. For the pressure-driven flow, the velocity in the vicinity of the wall was smaller than that in the bulk flow due to the non-slip condition. The diffusivities in the vicinity of the wall were smaller than those in the bulk flow for both the electroosmotic flow and the stationary flow because of the interaction between the ion motion and the microchannel wall.
