Wettävyyttä

Wettävyyttä is a Finnish term that translates to "wettability" in English. It refers to the ability of a liquid to maintain contact with a solid surface, resulting from intermolecular interactions when the two are brought together. This property is determined by a balance between adhesive forces between the liquid and the solid, and cohesive forces within the liquid. Wettability is a crucial factor in many natural phenomena and industrial processes.

The degree of wettability is typically measured by the contact angle, which is the angle formed by a liquid droplet at the point of contact with a solid surface. A low contact angle (less than 90 degrees) indicates that the liquid spreads out on the surface and wets it well, signifying strong adhesive forces. Conversely, a high contact angle (greater than 90 degrees) suggests that the liquid beads up and has poor wettability, indicating stronger cohesive forces within the liquid compared to the adhesive forces with the solid. A contact angle of exactly 90 degrees means the adhesive and cohesive forces are balanced.

Wettability plays a significant role in various fields. In biology, it influences phenomena like water transport in plants and the adhesion of cells. In industry, it is vital in applications such as painting, printing, coating, and the effectiveness of detergents and adhesives. For example, understanding and controlling wettability allows for the development of water-repellent fabrics or surfaces that are easily cleaned. The surface energy of the solid and the surface tension of the liquid are key determinants of wettability. Modifying the surface properties of materials can intentionally alter their wettability for specific purposes.