Test liquids can be used to probe the surface properties of materials. They form a
characteristic angle on the boundary between the solid, the liquid, and the vapor.
I many case one can obtain valueable information about a materials by this method.
In the surface modification group of the IAP a Krüss K40 video goniometer is used
for contact angle measurements. The surface free energy and their components are
determined with a number of different methodes including dipers-polar and acid-base
models.
For further information on contact angle goniometry visit
www.polymer-analysis.com/surfaces/contact_angle.html