Spacial and temporal dynamics of the volume fraction of the colloidal particles inside a drying sessile drop

TL;DR

This paper models the drying process of colloidal droplets using lubrication theory, accounting for shape evolution and particle concentration, with results aligning with experimental data.

Contribution

It introduces a simple model that describes the temporal dynamics of drop shape and particle volume fraction during drying, incorporating viscosity dependence on concentration.

Findings

Final drop shapes depend on initial particle volume fraction and capillary number.

Simulation results agree reasonably with experimental data.

Model applied to aqueous human serum albumin solutions.

Abstract

Using lubrication theory, drying processes of sessile colloidal droplets on a solid substrate are studied. A simple model is proposed to describe temporal dynamics both the shape of the drop and the volume fraction of the colloidal particles inside the drop. The concentration dependence of the viscosity is taken into account. It is shown that the final shapes of the drops depend on both the initial volume fraction of the colloidal particles and the capillary number. The results of our simulations are in a reasonable agreement with the published experimental data. The computations for the drops of aqueous solution of human serum albumin (HSA) are presented.