Overview
EN ISO 19403-6:2024 (Paints and varnishes - Wettability - Part 6) specifies an optical method for measuring the dynamic advancing and dynamic receding contact angles by changing the volume of a liquid drop on a flat test surface. The method captures the contact angle while the three‑phase contact line moves (wetting or dewetting) and is used to characterize wettability, dewetting behavior, and the morphological/chemical homogeneity of solid surfaces relevant to paints, varnishes and coatings.
Key topics and requirements
- Measurement principle: A liquid drop is dosed onto a horizontal test specimen and its volume is continuously increased (measuring the dynamic advancing contact angle) or decreased (measuring the dynamic receding contact angle).
- Optical detection: Contact angle determination is made optically; systems with digital image capture and analysis are preferred.
- Data method: The contact angle is preferably derived using the polynomial fitting method, synchronized with dosing.
- Repetition: The procedure is repeated with at least two drops to ensure repeatability.
- Scope limitations: This part describes only the method based on changing the drop volume (other dynamic methods, e.g. moving the drop or immersing/withdrawing solids, are outside this part).
- Use for surface energy: When determining polar and dispersive components of surface free energy (see ISO 19403‑2), the dynamic advancing contact angle shall be used; the dynamic receding contact angle is not recommended for surface energy determination.
- Test preparation: The standard addresses system setup, conditioning of test panels and test liquids, measurement conditions, evaluation and test reporting (see clauses on apparatus, sampling, procedure, evaluation and test report).
Applications and users
Practical applications of EN ISO 19403-6:2024 include:
- Quality control of coatings, primers and surface treatments to monitor wetting/dewetting performance.
- R&D for paint and varnish formulation (optimizing wetting agents, additives and surface treatments).
- Failure analysis and adhesion assessment where dynamic wetting behavior or contact angle hysteresis indicates surface heterogeneity or contamination.
- Certification and inter‑laboratory testing in materials labs and contract testing.
Primary users: coatings manufacturers, test laboratories, materials scientists, surface engineers, equipment suppliers and standards/quality managers.
Related standards
- ISO 19403-1:2022 - Vocabulary and general principles (wettability)
- ISO 19403-2:2024 - Surface free energy determination by contact angle (uses dynamic advancing angle)
- ISO 4618 - Paints and varnishes vocabulary
- ISO 15528 - Sampling for paints and varnishes
Keywords: dynamic contact angle, advancing contact angle, receding contact angle, contact angle measurement, drop volume method, wettability, paints and varnishes, surface free energy, contact angle hysteresis.
