hydrofobiske

Hydrofobiske describes the quality of being repelled by water or having a tendency to avoid contact with it. In chemistry and biology, substances, surfaces, or interactions described as hydrophobic are typically nonpolar or only weakly polar, and thus have little affinity for water molecules. The term is often used to contrast with hydrophilic, which readily interacts with water.

The physical basis lies in nonpolar interactions and the hydrophobic effect. Water molecules form a structured hydrogen-bond network; surrounding a nonpolar solute requires costly rearrangements. By aggregating nonpolar groups, or by forming droplets, the system releases some water molecules, increasing entropy. This drive for entropy leads to clustering of hydrophobic moieties in many systems, such as micelles or lipid bilayers.

Measurements and indicators: the degree of hydrophobicity can be assessed by water contact angle on a surface; higher angles indicate stronger hydrophobicity. The octanol-water partition coefficient (logP) is a common metric for solubility and hydrophobicity of organic compounds.

Examples and relevance: hydrocarbons, oils, fats, waxes are hydrophobic; many proteins have hydrophobic cores, while hydrophilic residues are exposed to solvent; cell membranes present a hydrophobic interior. In everyday life, hydrofobiske surfaces cause water to bead on leaves or textiles; they are used in coatings, textiles, and anti-fouling materials. In formulation science, hydrophobic drugs and carriers influence solubility and delivery.