Why is this important to measure?
Dynamic contact angle (DCA) measurements are made using a Cahn DCA 500 Analyser. The apparatus uses the Wilhelmy plate method for measuring the forces exerted as the solid/liquid phase boundary is moved along the sample surface are measured. The contact angle is calculated from the forces of interaction, sample geometry and liquid surface tension. Both the advancing (Øadv) and receding (Ørec) angles can be measured. The difference (Øadv-Ørec) is the contact angle hysteresis.
Wilhelmy plate method
The surface tension of a liquid can be determined in the same way using a standard substrate having a known contact angle, e.g. glass