Amplifying and attenuating the coffee-ring effect in drying sessile nanofluid droplets
A. Crivoi and Fei Duan
Accepted
The experiments and simulations to promote or attenuate the "coffee-ring effect" for the pinned sessile nanofluid droplets are presented. The addition of surfactant inside the water suspension of aluminum oxide nanoparticles results in the coffee-ring formation after the pinned sessile droplets are fully dried on a substrate, while the droplets of the same suspension without the surfactant produce a fine uniform coverage. The mathematical model based on the Diffusion Limited Cluster-Cluster Aggregation (DLCA) approach has been developed to explain the observed difference in the experiments. The simulations show that the particle sticking probability is a crucial factor on the morphology of finally dried structures.