Hidrofóbico

Hidrofóbico is a term derived from Greek roots, meaning "water-fearing." It describes the property of a substance that repels water. Substances that are hydrophobic are generally nonpolar and do not dissolve well in polar solvents like water. This is due to the nature of intermolecular forces; water molecules are highly attracted to each other through hydrogen bonds, and they tend to exclude nonpolar molecules that cannot participate in these bonds.

In chemistry, hydrophobic interactions are a significant force driving molecular self-assembly, particularly in biological systems. For example, the folding of proteins in an aqueous environment often involves hydrophobic amino acid residues clustering together in the interior of the protein, shielded from water. Similarly, cell membranes are formed by a lipid bilayer, with the hydrophobic tails of the lipid molecules facing inwards, away from the aqueous environment inside and outside the cell.

Examples of hydrophobic materials include oils, fats, and many plastics. Surfaces treated to be hydrophobic can cause water to bead up and roll off, a phenomenon often referred to as the lotus effect. This property is utilized in various applications, such as water-repellent coatings for textiles, self-cleaning surfaces, and in the design of microfluidic devices. The degree of hydrophobicity can be quantified by contact angle measurements, where a higher contact angle indicates a more hydrophobic surface.