kontaktszög

Kontaktszög is a term of German origin that translates to "contact angle" in English. It is a fundamental concept in surface science and chemistry, referring to the angle formed by a liquid droplet at the interface with a solid surface. Specifically, it is the angle between the tangent to the liquid surface at the point of contact and the solid surface itself.

The kontaktszög is a measure of the wettability of a solid surface by a liquid. A small kontaktszög, typically less than 90 degrees, indicates that the liquid wets the surface well, spreading out across it. This occurs when the adhesive forces between the liquid and the solid are stronger than the cohesive forces within the liquid. Conversely, a large kontaktszög, greater than 90 degrees, signifies poor wettability, where the liquid beads up on the surface. This happens when the cohesive forces of the liquid are stronger than the adhesive forces to the solid.

Factors influencing the kontaktszög include the surface tension of the liquid, the surface energy of the solid, and the presence of any contaminants on the solid surface. The kontaktszög is an important parameter in various applications, such as printing, coating, adhesion, and microfluidics, as it directly affects how liquids interact with and spread on solid materials. It is typically measured using optical methods, such as goniometry.