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Predicting coffee ring formation upon drying in droplets of particle suspensions
Michael J Hertaeg1, Clare Rees-Zimmerman2, Rico F Tabor3
1BioPRIA and Department of Chemical Engineering, Monash University, Clayton, VIC 3800, Australia.
Journal of Colloid and Interface Science
|February 16, 2021
Summary
Researchers developed a model to predict coffee ring formation in drying colloidal systems. Ring patterns form at low contact angles, dependent on initial suspension concentration, aiding manufacturing processes.
Area of Science:
- Colloid science
- Materials science
- Fluid dynamics
Background:
- Pattern formation is prevalent in drying colloidal systems.
- The 'coffee ring effect' describes particle accumulation at the droplet edge, posing challenges in manufacturing.
- Understanding and predicting this phenomenon is crucial for industrial applications.
Purpose of the Study:
- To present a predictive model for coffee ring formation in hard spherical particle systems.
- To identify key parameters influencing the development of ring deposits.
- To validate model predictions against experimental data.
Main Methods:
- Development of a mathematical model to simulate drying colloidal droplets.
- Investigation of the influence of contact angle and initial particle concentration.
- Experimental validation using latex particle suspensions.
Main Results:
- The model successfully predicts the occurrence of coffee ring patterns.
- Ring formation is strongly correlated with low contact angles.
- The specific contact angle for ring formation is determined by the initial suspension concentration.
Conclusions:
- The developed model provides a reliable method for predicting coffee ring effects.
- Contact angle and initial concentration are critical factors governing deposit patterns.
- Findings offer insights for controlling or preventing unwanted ring formation in industrial processes.
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