Kontaktvinker

Kontaktvinker, also known as contact angles, are a fundamental concept in surface science and physics. They measure the inclination of a liquid surface to the surface of a solid at the point where the liquid, solid, and gas phases meet. This three-phase contact line is critical in determining how a liquid will spread or bead on a solid surface.

The contact angle is typically measured using optical methods, where a goniometer captures an image of a liquid droplet on the solid surface. The angle is then geometrically determined from this image. A contact angle of 0 degrees indicates complete wetting, meaning the liquid spreads out perfectly over the surface. Conversely, a contact angle of 180 degrees signifies complete non-wetting, where the liquid forms a perfect sphere and minimizes contact with the solid. Angles between these extremes represent varying degrees of wetting.

Factors influencing the contact angle include the surface tension of the liquid, the surface energy of the solid, and the presence of any contaminants or adsorbed layers on the solid surface. The chemical nature of both the liquid and solid, as well as their surface roughness, play significant roles. Understanding contact angles is vital in numerous applications, such as adhesion, lubrication, coating processes, microfluidics, and the design of self-cleaning surfaces. For instance, a low contact angle is desired for effective paint spreading, while a high contact angle is sought after for water-repellent fabrics.