New Stood-up Drop method unlocks dewetting for surface QC

Krüss has introduced a new dosing system for its contact angle measuring instruments that enables rapid measurement of drop retraction behaviour. This method, called the Stood-up Drop, enhances the application possibilities of wetting measurements, particularly for testing material surfaces.

Surface properties such as coatability, cleanliness, and adhesiveness are often tested for wettability as part of industrial quality control. However, dewetting, or the contraction of liquid on a surface, has been less explored, despite its value in assessing materials like hydrophobic and self-cleaning surfaces. Dewettability is sensitive to material pretreatment, making it a valuable test criterion. The critical result is the receding contact angle, which is now more easily measured with Krüss’s Stood-up Drop method.

The Stood-up Drop system works by placing a drop of water on a sample with controlled dynamics. The liquid spreads and contracts into a defined drop, which is captured by a camera and analysed to determine the receding contact angle. This process takes just seconds.

The speed and ease of the Stood-up Drop method make it suitable for quality control across large sample sets, a previously difficult task. Predefined measuring sequences and dosing parameters ensure reliable, user-independent results. Additionally, this method is safer than test inks, as it avoids harmful substances, while still covering similar applications.

Measuring the receding angle can complement or even replace other surface testing methods. Extensive tests have shown strong correlations between receding angle measurements and pretreatment processes like corona, plasma, and flame treatments. In some cases, prescreening with this method has reduced the need for more complex tests, such as Moisture Vapour Transmission Rate (MVTR) measurements used to assess moisture protection and breathability.

The Stood-up Drop dosing unit is now available for all Krüss Drop Shape Analyzer instruments. To provide more insight, Krüss is offering a free three-part webinar series on the method’s wide-ranging applications.

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