title: Role of hydroxyls in oxide wettability.
abstract: Oxides are believed to be hydrophilic because of the strong affinity for hydroxylation at their surfaces. This letter explores the relationship between the hydroxylation of oxide surfaces and their resulting wettability. Here we demonstrate that hydroxyls increase the hydrophobicity, or reduce the wettability, of oxide surfaces by reducing the polar component of surface free energy. Using alumina as a model material, increased hydrophobicity with hydroxylation was confirmed experimentally and a correlation between the strength of the hydroxyl-driven hydrophobic response and surface treatment was demonstrated.
authors.affiliation: Mechanical Engineering Department, 3123 TAMU, Texas A&M University, College Station, Texas, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: Gentleman
authors.forename: J A
authors.initials: JA
authors.lastname: Ruud
mesh_terms: D006868:Hydrolysis; D057927:Hydrophobic and Hydrophilic Interactions; D006878:Hydroxides / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry; D013816:Thermodynamics; D017155:Wettability
chemical_list: D006878:Hydroxides; D010087:Oxides; D012822:Silicon Dioxide