Colloquium: "Themes in complex fluids: from thin films to electrokinetically controlled transport"

Professor Howard A. Stone is ​2022/2023 Sackler lecturer of the Mortimer and Raymond Sackler Institute of Advanced Studies.

Abstract:

Fluid dynamical phenomena occur from large scales important to Earth-relevant processes, e.g., climate and geophysical phenomena, to small scales, hundreds of microns and smaller, such as those that influence and transport cells, colloids, and polymers. In this talk, I will first give a glimpse of some (randomly selected), perhaps unexpected, fluid dynamical phenomena that my group has worked on. Then, I will focus on problems in colloid transport where electrokinetic effects dominate. In particular, diffusiophoretic transport refers to the relative motion of fluid and suspended particles due to a gradient of a chemical, where the transport rate is controlled by the diffusivity of the small ions. I will survey a few of our results in this area, including transport in porous media, the influence of multivalent ions, the role of a background electrolyte or pH, and effects that influence the dispersion of a cloud of colloids.