The Effect of Electrolyte on Diffusiophoresis in One-Dimensional Salt Gradients

We study the diffusiophoretic motion of negatively charged particles in one dimensional salt gradients using a dead-end pore geometry and various salt solutions. We estimate the diffusiophoretic velocities for particles for a range of background electrolytes such as multi-valent and asymmetric (non-z:z) electrolytes. Theoretical investigations of asymmetric electrolyte diffusiophoresis support our findings that the choice of electrolyte significantly influences the movement of particles, and in particular the chemiphoretic component of the diffusiophoretic velocity. By combining theoretical and experimental analysis, we present the relative importance of electrophoretic and chemiphoretic contributions in electrolyte solutions.