title: Amplifying and attenuating the coffee-ring effect in drying sessile nanofluid droplets.
abstract: Experiments and simulations to promote or attenuate the "coffee-ring effect" for pinned sessile nanofluid droplets are presented. The addition of surfactant inside a water suspension of aluminum oxide nanoparticles results in coffee-ring formation after the pinned sessile droplets are fully dried on a substrate, while droplets of the same suspension without the surfactant produce a fine uniform coverage. A mathematical model based on diffusion-limited cluster-cluster aggregation 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.
authors.affiliation: School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798.
authors.forename: A
authors.initials: A
authors.lastname: Crivoi
authors.forename: Fei
authors.initials: F
authors.lastname: Duan