Amplifying and attenuating the coffee-ring effect in drying sessile nanofluid droplets

• Main Authors: Duan, Fei, Crivoi, Alexandru
• Other Authors: School of Mechanical and Aerospace Engineering
• Format: Article
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/96312; http://hdl.handle.net/10220/10214
• Institution: Nanyang Technological University

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.