TS EN ISO 19403-3

TS EN ISO 19403-3 is a method standard in the paints and varnishes field that addresses the optical determination of liquid surface tension by the pendant drop technique. The measurement converts the force balance at a hanging drop into a numerical value, which is particularly useful when characterizing coating materials.

What the pendant drop technique tells you

In the pendant drop method, the profile of a suspended droplet is analysed optically and used to calculate surface tension. Surface tension arises from cohesive forces within the liquid; as it changes, so does the droplet shape and the liquid’s tendency to spread over a surface. In coating technology, this is a core property because it helps explain wetting behaviour and how a liquid interacts with a substrate.

Documented application frame

• This part specifies an optical test method for measuring the surface tension of liquids.
• It states that the method can be applied to the characterization of liquid coating materials.
• It notes that applicability may be restricted for liquids with non-Newtonian rheology.
• The document belongs to the wettability series, so its technical focus is the surface-behaviour side of coating performance.
• This record corresponds to the TS EN ISO 19403-3 edition and its status is withdrawn.

From a general technical perspective, surface tension is one of the key properties influencing spreading, droplet formation and substrate interaction in paints, varnishes, inks, adhesives and similar liquids. In that sense, this standard is not only about a measurement procedure, but also about providing a consistent characterization tool for comparing coating liquids and supporting wetting-related evaluation.