Veetõrjuvad

Veetõrjuvad, also known as water-repellent or hydrophobic, describes the property of a material or surface that resists wetting by water. This resistance is due to the surface tension of water and the nature of the material's surface. When water comes into contact with a veetõrjuvad surface, the adhesive forces between the water molecules and the surface are weaker than the cohesive forces between the water molecules themselves. Consequently, the water tends to bead up and roll off rather than spreading out and soaking in.

This property is achieved through various means. For natural materials like certain leaves or feathers, it is an inherent structural characteristic, often involving microscopic structures that trap air and reduce the contact area with water. For manufactured items, veetõrjuvad finishes can be applied. These often involve chemical treatments that create a low surface energy coating. Common examples include waxes, silicones, or fluorocarbons.

Veetõrjuvad properties have numerous practical applications. In textiles, they are used to create waterproof or water-resistant clothing and outdoor gear, preventing rain and moisture from penetrating the fabric. In construction, veetõrjuvad treatments can protect building materials like wood, stone, and concrete from water damage, reducing degradation and preventing the growth of mold and mildew. Eyeglass lenses and camera lenses often feature veetõrjuvad coatings to repel water and smudges, improving visibility and ease of cleaning. Automotive applications include veetõrjuvad treatments for windshields, which help water bead and roll off at speed, improving visibility for drivers.