Benutzer:Stefriegel/Cassie's law
aus Wikipedia, der freien encyclopedia
Cassie's law, or the Cassie equation, describes the effective contact angle θc for a liquid on a chemically heterogeneous surface, i.e. the surface of a composite material consisting of different chemistries, that is non uniform throughout.[1] Contact angles are important as they quantify a surface's wettability, the nature of solid-fluid intermolecular interactions.[2] Cassie's law is reserved for when a liquid completely covers both smooth and rough heterogeneous surfaces.[3]
More of a rule than a law, the formula found in literature for two materials is;
where and are the contact angles for components 1 with fractional surface area , and 2 with fractional surface area in the composite material respectively. If there exist more than two materials then the equation is scaled to the general form of;
, with .[4]