fluidrepellent

Fluidrepellent refers to materials, coatings, or surfaces that resist wetting by liquids. Such surfaces promote droplet formation and shedding, reducing staining, fouling, and moisture uptake. Repellence is often described by the contact angle and contact angle hysteresis; higher angles and lower hysteresis indicate stronger liquid resistance. Realization typically combines low surface energy with surface roughness at micro- or nano-scales; sometimes a lubricating liquid is infused into a porous structure to create a slippery liquid-infused porous surface (SLIPS), enabling repellence to many liquids.

Classifications include hydrophobic (water-repellent), oleophobic (oil-repellent), and omniphobic (repels diverse liquids). Superhydrophobic materials have contact angles above roughly 150 degrees and very low hysteresis, often inspired by natural surfaces such as the lotus leaf. Chemistries frequently used include fluorinated polymers and siloxanes, as well as nano-structured coatings.

Applications cover textiles that resist moisture and stains, windshields, solar panels, and architectural or electronic coatings to reduce icing, fogging, or fouling. In medical devices, fluid repellence can limit biofilm formation and contamination.

Limitations include wear resistance, durability in dirty or oily environments, and environmental concerns associated with some fluorinated chemistries. Research aims to improve durability, broaden liquid repellence (omniphobicity), and scale manufacturing, including SLIPS and microstructured coatings.