Hydrophobic

Hydrophobic describes a surface that resists wetting by water, exhibiting high contact angles with polar liquids. In filtration this property influences pre‑wetting, bubble‑point and porometry tests (gas will pass more easily through unwetted pores), start‑up behaviour and fouling with mixed aqueous/oily streams. Hydrophobic surfaces can reduce water films that occlude pores, stabilising flux in some duties, but they may attract non‑polar foulants unless countered by appropriate cleaning and chemistry. Surface energy, roughness and coatings govern hydrophobicity; treatments such as fluorinated layers or plasma processes can render polymer meshes strongly water‑repellent. Engineers tune hydrophobicity to the application—highly hydrophobic for gas service where liquid hold‑up must be avoided, moderated behaviour for aqueous clarification to ensure reliable wet‑out—so that retention, flux and cleanability remain balanced. Specifications should document contact angle and its retention after defined CIP cycles and thermal exposure.