ISO 19403-4-2024 PDF

Full title and description

Paints and varnishes — Wettability — Part 4: Determination of the polar and dispersive fractions of the surface tension of liquids from an interfacial tension. This International Standard specifies an optical test method to determine the polar and dispersive fractions of a liquid’s surface tension by measuring interfacial tension and deriving the two contributions for characterization of liquid coating materials; it replaces the 2017 edition.

Abstract

This document specifies a test method using optical measurement of interfacial tension to calculate the polar and dispersive fractions of the surface tension of liquids. The method is intended primarily for liquid coating materials and is particularly useful where alternative measurement methods are affected by drying or evaporation; restrictions may apply for liquids with non‑Newtonian flow behaviour.

General information

• Status: Published.
• Publication date: 18 October 2024 (Edition 2, 2024).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 87.040 (Paints and varnishes).
• Edition / version: Edition 2 (2024).
• Number of pages: 8 pages (ISO PDF).

Scope

The standard defines an optical interfacial‑tension–based test procedure to determine the polar and dispersive components of the surface tension of liquids. It covers sample preparation, optical measurement of an interface (drop or pendant geometry as applicable), data reduction to separate polar and dispersive contributions, and reporting of results. The procedure is targeted at liquid coating materials and notes limitations when applied to non‑Newtonian fluids (reference to ISO 3219‑1:2021 for rheology definitions).

Key topics and requirements

• Measurement principle: optical determination of interfacial tension followed by calculation of polar and dispersive surface‑tension fractions.
• Instrumentation: optical imaging/analysis of interfacial geometry (drop/pendant or equivalent) and software for curve‑fitting and data reduction.
• Sample considerations: handling of volatile or drying liquids and warnings on applying the method to non‑Newtonian fluids.
• Data reporting: required reporting elements (measured interfacial tension, calculated polar/dispersive fractions, test conditions and uncertainties) to ensure reproducibility.
• Traceability and verification: use of reference materials or check procedures to validate measurement arrangements (consistent with the ISO 19403 series approach).

Typical use and users

Laboratories and quality‑control units in paint, varnish and coating manufacturers; adhesive and sealant formulators; surface‑science and materials research groups; instrument manufacturers and calibration facilities; and certification/accreditation bodies evaluating wettability and surface‑energy properties of liquid coatings. The method is used where a robust separation of polar and dispersive contributions is needed or when other methods are compromised by drying/evaporation.

Related standards

ISO 19403 is a multi‑part series on wettability and optical measurement methods for coatings and substrates. Relevant parts (revised in 2024/2025 cycle) include: ISO 19403‑1 (terminology and general principles), ISO 19403‑2 (surface free energy of solids by contact angle), ISO 19403‑3 (surface tension of liquids by pendant drop), ISO 19403‑5 (determination of polar/dispersive fractions from contact angles on a purely dispersive solid), ISO 19403‑6 and ISO 19403‑7 (dynamic contact angles and roll‑off/dynamic measurements). National/adopted equivalents (e.g., BS EN, ÖNORM, UNE) exist for many parts.

Keywords

wettability; surface tension; polar fraction; dispersive fraction; interfacial tension; optical measurement; coatings; contact angle; pendant drop; surface free energy.

FAQ

Q: What is this standard?

A: ISO 19403‑4:2024 is an International Standard that specifies an optical interfacial‑tension method to determine the polar and dispersive fractions of the surface tension of liquids, primarily for liquid coating materials.

Q: What does it cover?

A: It covers the measurement principle (optical interfacial tension), sample‑handling notes, calculation of polar and dispersive components from measured interfacial data, reporting requirements and limitations (notably for non‑Newtonian fluids).

Q: Who typically uses it?

A: Coatings and paint manufacturers, adhesives/sealants formulators, laboratory and R&D groups working on surface science, instrument vendors, and accreditation bodies performing wettability and surface‑energy testing.

Q: Is it current or superseded?

A: It is current (published October 2024, Edition 2) and supersedes the previous ISO 19403‑4:2017 edition.

Q: Is it part of a series?

A: Yes — ISO 19403 is a multipart series addressing wettability and optical measurement methods for paints, varnishes and coatings (parts 1–7 and related revisions). Users commonly consult several parts together (e.g., parts 2 and 3) depending on whether the target is a solid’s surface energy or a liquid’s surface tension.

Q: What are the key keywords?

A: Wettability, surface tension, polar fraction, dispersive fraction, interfacial tension, contact angle, coatings, pendant drop, optical measurement.