Dynamic contact angle analyzer

The Dynamic contact angle analyser (DCA) is an instrument used to measure the contact angle that a liquid forms with a solid and explore the wettability of the solid sample. It is one of the surface outermost investigation.
To measure the contact angle, the solid sample - which is usually in plate form - is immersed in a liquid with known surface tension. The contact angle is calculated from the change of weight by slowly immersing and then withdrawing the sample. The advancing angle (maximum angle) is determined during the wetting process and the receding angle (minimum angle) during the de-wetting process. The difference between the two contact angle is defined as “contact angle hysteresis” which can be related to the sample surface roughness or composition heterogeneity.
The results for the contact angle measurements can be used to determine the surface tension of solids.
The results of the measurements can be used to follow the surface changes due to chemical reactions or physical modification. It is important in the biomedical material characterization, adhesive and coating applications.
By using a proper solid, which forms a null contact angle with the liquids (such as metals or accurately cleaned glass), the surface tension of a liquid can be measured.