Automated Evaluation of Contact Angles in a Three-Phase System of Selective Agglomeration in Liquids


  • Julia Schreier Inst. f. Micro-Process-Engineering and Particle Technology (IMiP) Umwelt-Campus Birkenfeld
  • Orkun Furat Institute of Stochastics Ulm University
  • Murat Cankaya Institute of Stochastics Ulm University
  • Volker Schmidt Institute of Stochastics Ulm University
  • Ulrich Bröckel Inst. f. Micro-Process-Engineering and Particle Technology (IMiP) Umwelt-Campus Birkenfeld



automated detection, contact angle, image data, parametric contour modelling, selective agglomeration, three-phase system


This study aims to an automated evaluation of contact angles in a three-phase system of selective agglomeration in liquids. Wetting properties, quantified by contact angles, are essential in many industries and their processes. Selective agglomeration as a three-phase system consists of a suspension liquid, a heterogeneous solid phase and an immiscible binding liquid. It offers the chance of establishing more efficient separation processes because of the shape-dependent wetting properties of fine particles (size ≤ 10 µm). In the present paper, an experimental setup for contact angle measurements of fine particles based on the Sessile Drop Method is described. Moreover, a new algorithm is discussed, which can be used to automatically compute contact angles from image data captured by a high-speed camera. The algorithm uses a marker-based watershed transform to segment the image data into regions representing the droplet, the carrier plate coated by fine particles, and the background. The main idea is a parametric modelling approach forthe time-dependent droplet’s contour by an ellipse.

The results show that the development of the dynamic contact angles towards a static contact angle can be efficiently determined based on this novel technique. These findings are useful for a detailed discrimination of wetting properties of spherical and irregularly shaped particles as well as their wetting kinetics. Also, a better understanding of selective agglomeration processes will be promoted by this user-friendly method.


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How to Cite

Schreier, J., Furat, O., Cankaya, M., Schmidt, V., & Bröckel, U. (2020). Automated Evaluation of Contact Angles in a Three-Phase System of Selective Agglomeration in Liquids. Image Analysis and Stereology, 39(3), 187–196.



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