Professional contact angle measurement and droplet shape analysis are fundamental techniques in surface science used to evaluate wettability, surface energy of solids, and surface tension of liquids. Using a goniometer or optical tensiometer, the behavior of a liquid droplet on a surface is analyzed to determine whether it is hydrophobic or hydrophilic.

These techniques are primarily used for:

Determining wettability: They evaluate a liquid's ability to spread across a surface. A low angle indicates high wettability (hydrophilic), while a high angle indicates repulsion (hydrophobic).

Calculating surface free energy: They allow us to understand the reactivity and adhesive forces of a solid material, which is crucial for ensuring that paints, adhesives, or coatings adhere correctly.

Quality control and cleaning: They are used to detect invisible contaminants. If a surface is dirty, the contact angle of a water droplet will change drastically compared to the standard. Measuring surface and interfacial tension: By analyzing the shape of a "pendant drop," the cohesive force of a liquid or the tension between two immiscible liquids can be calculated.

Optimizing industrial processes:
Agriculture: Improves pesticide adhesion to leaves.
Electronics: Ensures the adhesion of inks and polymers to circuit boards.

Source: TA Instruments
Date: March 19, 2026