Virginia TechMastropietro, Dean J.Ducker, William A.2013-12-102013-12-102012-03-05Mastropietro, Dean J. ; Ducker, William A., Mar 5, 2012. “Forces between Hydrophobic Solids in Concentrated Aqueous Salt Solution,” PHYSICAL REVIEW LETTERS 108(10): 106101. DOI: 10.1103/PhysRevLett.108.1061010031-9007http://hdl.handle.net/10919/24504Much research has focused on the discovery and description of long-ranged forces between hydrophobic solids immersed in water. Here we show that the force between high contact-angle solids in concentrated salt solution (1 M KCl) agrees very well with van der Waals forces calculated from Lifshitz theory for separations greater than 5 nm. The hydrophobic solids are octadecyltrichlorosilane-coated glass, with an advancing contact angle of 108 degrees. Thus, in 1 M salt solution, it is unnecessary to invoke the presence of a hydrophobic force at separations greater than 5 nm. Through measurement in salt solution, we avoid the necessity of accounting for large electrostatic forces that frequently occur in pure water and may obscure resolution of other forces.application/pdfen-USIn CopyrightSurfactant-coated surfacesMonte carlo simulationLong-rangeBoundary-conditionThin filmsAttractionWaterMicroscopyParticlesInterfacesPhysicsArticle - Refereedhttp://link.aps.org/doi/10.1103/PhysRevLett.108.106101https://doi.org/10.1103/PhysRevLett.108.106101