Diffusiophoresis in the presence of a pH gradient

Suin Shim, Janine K. Nunes, Guang Chen, Howard A. Stone

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Diffusiophoresis is the spontaneous motion of particles under gradients of solutes. In electrolyte-driven diffusiophoresis, the zeta potential of the particles is an important surface property that characterizes diffusiophoretic mobility. However, the zeta potential is not a fixed material property and colloidal surfaces often show varying potentials depending on the physicochemical properties of the surrounding fluid, e.g., solute type, ionic strength, and pH. In this paper, we study experimentally and theoretically pH-dependent diffusiophoresis of polystyrene particles using a dead-end pore geometry. In particular, the influence of the isoelectric point (pI) on diffusiophoresis is demonstrated in the absence and presence of wall diffusioosmosis. Throughout the paper, we show with experiments and model calculations how the pH-dependent diffusiophoresis and diffusioosmosis influence the particle motion in dead-end pore configurations, including changes that occur when there is a sign change in the zeta potential near the pI.

Original languageEnglish (US)
Article number110513
JournalPhysical Review Fluids
Issue number11
StatePublished - Nov 2022

All Science Journal Classification (ASJC) codes

  • Computational Mechanics
  • Modeling and Simulation
  • Fluid Flow and Transfer Processes


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