In the adhesive industry, attention must be paid to the wettability of a part to be joined. Wetting is the formation of a contact surface between the adhesive and the part to be joined. The extent of wetting depends on the type of adhesive and the nature of the surface to be joined, such as: B. their chemical composition and roughness.

Many functional properties of surfaces to be joined depend largely on their wettability. Examples of such functional properties include the ability to self-clean, prevent contamination, ice formation, and moisture fogging, as well as the utility for purifying water, separating water-oil mixtures, and producing water by condensing atmospheric moisture.

The extent of wetting is often determined by the contact angle. The following cases are distinguished:

• From Non-wetting one speaks when the contact angle is greater than 90°. The liquid on the solid surface contracts into an almost spherical drop.
• From partial wetting is used when the contact angle is greater than 0° and less than 90°. The liquid on the surface forms a round cap.
• From complete wetting This is when the liquid spreads out on the surface of the solid in the form of a flat film. This scenario corresponds to a macroscopic contact angle of 0°.