Issue 35, 2019

Uncertainties in contact angle goniometry


The most widely used method to quantify the wetting properties of surfaces is by measuring contact angles. Even though contact angle goniometry is a powerful technique for characterizing wetting properties, it is not accurate for very hydrophobic surfaces. As the technique relies on image processing, it has inherent errors due to optical limitations, especially near the three-phase contact line. This leads to uncertainties in the positioning of the baseline, which can cause large errors in the measured contact angles. In this paper, we systematically evaluate these errors both theoretically and experimentally, focusing on the importance of image resolution. For ∼9 microliter droplet, displacement of the baseline by a single pixel leads to errors of approximately ±0.5° to ±1° for contact angles up to 150°, and errors increase rapidly in the superhydrophobic regime, up to ±8°. The error in the contact angle can be slightly reduced by increasing the image resolution, but cannot be eliminated entirely.

Graphical abstract: Uncertainties in contact angle goniometry

Supplementary files

Article information

Article type
19 Jun 2019
14 Aug 2019
First published
19 Aug 2019
This article is Open Access
Creative Commons BY license

Soft Matter, 2019,15, 7089-7096

Uncertainties in contact angle goniometry

M. Vuckovac, M. Latikka, K. Liu, T. Huhtamäki and R. H. A. Ras, Soft Matter, 2019, 15, 7089 DOI: 10.1039/C9SM01221D

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