Interfacially driven transport theory: a way to unify Marangoni and osmotic flows
We show that the solvent behaviour in both diffusio-osmosis and Marangoni flow can be derived from a simple model of colloid–interface interactions. We demonstrate that the direction of the flow is regulated by a single value of the attractive parameter covering the purely repulsive and attractive–repulsive interaction cases. The proposed universality between diffusio-osmosis and Marangoni flow is extended further to include diffusio-phoresis. In particular, an object immersed to a colloidal solution moves towards the low concentration of the colloidal particles in the case of colloid–interface repulsion and towards the high concentration of the colloidal particles in the case of colloid–interface attraction. The approach combines the methods of fluid dynamics, molecular physics and transport phenomena and provides a tractable explanation of how the colloid–interface interactions affect the momentum balance and the transport phenomena (interfacially driven transport).