ASTM D1331-20 (2024) PDF

Full title and description

ASTM D1331-20 (reapproved 2024) — Standard Test Methods for Surface and Interfacial Tension of Solutions of Paints, Solvents, Solutions of Surface-Active Agents, and Related Materials. Procedures for measuring surface tension and interfacial tension using du Noüy ring and Wilhelmy plate methods, intended for paints, solvents, surfactant solutions and related liquids.

Abstract

This standard describes four accepted laboratory methods for determining surface tension and interfacial tension of liquid materials: du Noüy ring and Wilhelmy plate techniques for both surface and interfacial measurements. It provides guidance on applicability to aqueous and non‑aqueous solutions, two‑phase systems, and paints or pigmented liquids, and specifies SI units for reporting results.

General information

• Status: Active (reapproved).
• Publication date: Approved Dec 1, 2020; published January 2021; reapproved June 24, 2024 (issued as D1331-20R24).
• Publisher: ASTM International (Committee D01/Subcommittee D01.24).
• ICS / categories: ICS 71.100.40 (Surface-active agents); ASTM technical area D01 (Paints and related coatings).
• Edition / version: D1331-20 (R24 reapproval, 2024).
• Number of pages: 6 pages.

Scope

The standard covers determination of surface tension and interfacial tension for a variety of liquid materials including paints, solvents and solutions of surface‑active agents. It defines four methods: Method A — Surface tension by du Noüy ring; Method B — Interfacial tension by du Noüy ring; Method C — Surface tension by Wilhelmy plate; Method D — Interfacial tension by Wilhelmy plate. Applicability notes address aqueous and nonaqueous solutions, two‑phase systems, and practical considerations for pigmented paints and viscous liquids.

Key topics and requirements

• Test methods: du Noüy (ring) and Wilhelmy (plate) procedures for surface and interfacial tension.
• Scope of application: aqueous solutions, nonaqueous solutions, mixed solvents, two‑phase mixtures and paints.
• Instrumentation: use of tensiometers (du Noüy ring or Wilhelmy plate configuration) and necessary buoyancy or correction considerations.
• Reporting: values expressed in SI units (dyne·cm or mN/m) and requirement to report test temperature.
• Precision/bias: precision established from interlaboratory studies (referenced research report for precision data).
• Referenced practices: related ASTM terminologies and interlaboratory practice for precision and bias.

Typical use and users

Used by coatings and paint manufacturers, surfactant and detergent producers, solvent formulators, petrochemical and lubricant labs, adhesives and ink developers, quality control and R&D laboratories, and academic researchers assessing wetting, spreading and interfacial behavior of liquids.

Related standards

Commonly referenced standards and practices include ASTM D459 (terminology for soaps and detergents), ASTM D971, ASTM D1417, ASTM D1590 (other tension test methods), and ASTM practices E177 and E691 for precision and interlaboratory study procedures. The standard sits within the ASTM D01 series on paints and related materials.

Keywords

surface tension, interfacial tension, du Noüy ring, Wilhelmy plate, tensiometer, surfactants, paints, solvents, wetting, dyne/cm, mN/m, ASTM D1331

FAQ

Q: What is this standard?

A: ASTM D1331-20 (reapproved 2024) is a set of laboratory test methods for measuring surface tension and interfacial tension of paints, solvents, surfactant solutions and related liquids using du Noüy ring and Wilhelmy plate techniques.

Q: What does it cover?

A: It covers four methods (surface and interfacial tension by du Noüy ring and by Wilhelmy plate), guidance on applicability to aqueous and nonaqueous systems, two‑phase mixtures, instrumentation considerations, units and reporting, and references for precision and related terminology.

Q: Who typically uses it?

A: Quality control and R&D laboratories in coatings, surfactants, inks, adhesives, lubricants, petrochemicals, and academic research groups assessing wetting, spreading, formulation performance and interfacial interactions.

Q: Is it current or superseded?

A: The D1331-20 edition is current and was reapproved in 2024 (designation D1331-20R24). It supersedes earlier editions (for example D1331-14 and prior revisions) and is not listed as superseded as of the reapproval date.

Q: Is it part of a series?

A: Yes — it is part of the ASTM D01 series on paints and related coatings/materials and is developed by Subcommittee D01.24 (physical properties of liquid paints and paint materials). It is commonly used alongside related ASTM test methods for interfacial and surface measurements.

Q: What are the key keywords?

A: Surface tension, interfacial tension, du Noüy ring, Wilhelmy plate, tensiometer, surfactant, paint, solvent, wetting, dyne/cm, mN/m.