ASTM D8597-24 - Standard Test Method for Surface Wettability of Coatings, Substrates, and Pigments by Contact Angle Measurement Using Portable Goniometers

1.1 This test method covers the measurement of the angle of contact of a drop of liquid applied to a surface when using a portable (that is, handheld) goniometric device to deposit the liquid and obtain the measurement.

1.2 This test method is intended to supplement the manufacturer’s instructions for the device being used to make the measurements but is not intended to replace them.

1.3 The choice of test liquid depends on the type of analysis being performed. Many liquids such as solvents, surfactant, and dispersant solutions can be used providing they are compatible with the construction of the particular instrumentation. Common test liquids include water, diiodomethane, ethylene glycol, formamide, and so forth.

1.4 This test method is based on goniometry, which involves the observation of a sessile drop of test liquid on a solid substrate.

1.5 Although contact angles are governed by surface free energy of the solid and the liquid, this test method cannot be used to measure surface tension directly. Contact angles can be used to estimate surface free energy of solid surfaces (Test Method D7490).

1.6 Units—The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.