oleophilic

Oleophilic describes a property of materials or surfaces that have an affinity for oils and other nonpolar organic liquids. In contrast to hydrophilic materials, which attract water, oleophilic substances readily interact with hydrocarbons and can absorb or spread oils. This behavior is commonly assessed by the tendency to wet with oil, often indicated by a low contact angle for oil on the surface and by high sorption of hydrocarbon liquids.

Oleophilicity arises from nonpolar interactions and lipophilic character, with van der Waals forces and limited hydrogen bonding to oils. Materials that are oleophilic typically exhibit low surface energy with respect to polar solvents, making them resistant to water but compatible with oil. The term is frequently used in material science and environmental engineering rather than in pure chemistry, and it is related to, but not identical to, lipophilicity.

Applications include oil spill response, where oleophilic sorbents such as pads, socks, or booms selectively absorb oil while repelling water. Oleophilic coatings and membranes are used to separate oil from water in industrial processes, and oleophilic soils or sponges aid in cleanup. In manufacturing, oleophilic materials are employed in lubrication, cleaning, and filtration systems where hydrocarbon oils are present.

Common oleophilic materials include polypropylene and polyurethane foams and fabrics used for oil sorption. Characterization can involve oil contact-angle measurements, oil/water partition coefficients, or sorption tests using representative hydrocarbon liquids.