hidrofiilisyyttä

Hydrophilicity refers to the property of a molecule or substance to be attracted to, absorb, or dissolve in water. The term is derived from Greek words, where "hydro" means water and "philos" means loving. Substances that exhibit hydrophilicity are considered polar and tend to form hydrogen bonds with water molecules. This attraction arises from the presence of polar functional groups, such as hydroxyl (-OH), carboxyl (-COOH), amino (-NH2), or ether (C-O-C) groups, within the molecule's structure. These groups can readily interact with the partial positive charges on hydrogen atoms or the partial negative charges on oxygen atoms of water molecules.

Conversely, substances that are repelled by water are called hydrophobic. Hydrophilic substances are soluble in water, whereas hydrophobic substances are not. This distinction is crucial in many scientific and industrial applications. For instance, in biology, cell membranes have hydrophilic surfaces facing the aqueous environments inside and outside the cell, while their hydrophobic interiors interact with lipid molecules. In chemistry, hydrophilicity influences a compound's solubility, its behavior in chromatography, and its ability to participate in chemical reactions in aqueous solutions. Detergents, for example, have both hydrophilic and hydrophobic parts, allowing them to emulsify oils and grease in water. The degree of hydrophilicity can be quantified using various methods, such as measuring water contact angles on surfaces or determining the partition coefficient of a molecule between water and an organic solvent.