Work Item
ASTM WK85412
New Test Method for Surface Wettability of Coatings, Substrates and Pigments by Contact Angle Measurement using Portable Goniometers
1. Scope
1.1 This practice covers the measurement of the angle of contact of a drop of liquid applied to a surface when using a portable (i.e. handheld) goniometric device to deposit the liquid and obtain the measurement. 1.2 Units - The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard. 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 The choice of test liquid depends upon the type of analysis being performed. Many liquids such as solvents, surfactant and dispersant solutions can be used as long as they are compatible with the construction of the particular instrumentation. Common test liquids include water, diiodomethane, ethylene glycol, formamide, etc. 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 free energy of the solid and the liquid, this standard cannot be used to measure surface tension directly. Contact angles can be used to estimate surface free energy of solid surfaces (ASTM D7490). 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 and health practices and determine the applicability of regulatory limitations prior to use.
Keywords
contact angle, surface tension, surface energy, wettability
Rationale
This practice focus on the use of portable goniometers for measuring contact angles of liquids on different substrates. This will be used in cases where the use of a portable goniometer is required. This sometimes is required for very large substrates that need to be measured and it & apos; not desirable or feasible to cut a portion of the sample and a sample taken to a bench top goniometer for measurement.
The title and scope are in draft form and are under development within this ASTM Committee.
Work Item Status
Date Initiated: 02-23-2023
Technical Contact: David Barnes
Item: 000
Ballot:
Status: