The Effect of Electrokinetic Potential on Evaporation of Colloidal Dispersion Droplets

Resumo

Experiments have been carried out to clarify the role of the electrokinetic potential (charge) of particles in the processes of evaporation of droplets of their aqueous dispersions and the formation of ring-shaped deposits (the coffee ring effect). The effects of the particle charge on the initial contact angle of a dispersion droplet, the angle of depinning, the morphology of a solid deposit, and the dynamics of droplet evaporation have been studied. It has been shown that a rise in the electrokinetic potential leads to an increase in the depinning angle, variations in the shape of a solid deposit, and a change in the scenarios of droplet evaporation. It has been assumed that the solvation interaction between a dispersed phase and a dispersion medium is the key factor in the phenomenon of depinning. The obtained results have been used to refine the mechanisms of the realization of different scenarios of the evaporation of dispersion droplets.