Hydrophobicité

Hydrophobicité, also known as hydrophobicity, describes the physical property of a molecule that is repelled by water. The term "hydrophobic" literally means "water fearing." Substances that exhibit hydrophobicité are generally nonpolar molecules, such as oils and fats. These molecules tend to aggregate together in aqueous solutions, minimizing their contact with the polar water molecules. This phenomenon is a consequence of the hydrophobic effect, which is a driving force in the self-assembly of biological molecules like proteins and lipid bilayers. Water molecules are highly polar due to the electronegativity difference between oxygen and hydrogen atoms, forming hydrogen bonds with each other. Nonpolar molecules cannot form these strong hydrogen bonds. When nonpolar molecules are introduced into water, the water molecules preferentially hydrogen bond with each other, effectively pushing the nonpolar molecules out of the aqueous phase. This leads to the separation of hydrophobic and hydrophilic (water-loving) components in a mixture. Surface tension plays a role in this process, as water's high surface tension is minimized when hydrophobic substances cluster together, reducing the overall surface area exposed to water.