ASTM D7334-08R22 - Standard Practice for Surface Wettability of Coatings, Substrates and Pigments by Advancing Contact Angle Measurement

1.1 This practice covers the measurement of the angle of contact when a drop of liquid is applied to a coated surface, substrate, or preformed disk of pigment.

1.2 There are two types of contact angles, advancing and receding. This standard deals only with advancing contact angles.

1.3 This practice is intended to supplement the manufacturer’s instructions for the device being used to make the measurements, but is not intended to replace them.

1.4 A common test liquid is water, but many other liquids such as solvents, surfactant and dispersant solutions and even liquid paints can be used.

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

1.6 Although contact angles are governed by surface tension, this standard cannot be used to measure surface tension directly.

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

1.8 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.

1.9 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.