Abstract
The purpose of this study is to experimentally reveal the effect of surfactant additives on the pressure loss of a microchannel with a height of 50 μm and on the Brownian motion of the nanoparticles in the vicinity of the wall surface. The tested surfactant solutions are a non-ionic surfactant, a cationic surfactant, and an anionic surfactant, and the density of the solutions is 1.0%. The Brownian motion is measured by an evanescent-wave microscopy system. As a result of the experiment, the pressure loss of the surfactant solutions increased compared to that of distilled water for 0.1 < Re < 9. In particular, the pressure loss of the non-ionic surface solution increased significantly. On the other hand, the zeta potential of the glass surface in the surfactant solutions was increased. Though the extent of the Brownian motion in the vertical direction was increased in the surfactants solutions, its extent in the horizontal direction was decreased compared to that in distilled water.
