The contact angle is the angle which is formed at the three-phase interface between a solid, a liquid drop and air or another gas.

Such measurements can be used to determine wettability, which provides an indication of how effectively a liquid will spread over a surface. The droplet can be formed from a liquid appropriate for the system being tested, for example water would be used to yield information regarding the hydrophilic/hydrophobic nature of a surface. Applications of contact angle measurement include the detection of contaminants on surfaces, quantifying the wettability of reinforcing materials for composites and determining the feasibility of applying coatings to surfaces. By measuring the contact angle with both polar and non-polar solvents, the surface free energy can be derived. This is analogous to surface tension for liquids.

External links

• Information regarding the technique of contact angle measurement can be found at the website of equipment manufacturer Data Physics
• An example case study of contact angle measurement, covering corona and flame treatment of polymers can be found at Azom

Who to contact

For more information on contact angle measurement please contact Dr Oliver Lewis.