Relation of Wettability by Aqueous Solutions to the Surface Constitution of Low-Energy Solids

摘要

The critical surface tension (y) of each solid thus obtained agrees well with previous values established from studies with various pure organic liquids. Aqueous solutions whose surface tensions are lower than 30 dynes/cm were found to spread on polyethylene, whereas no solution had a surf ace tension low enough to spread on Teflon. The ability of aqueous solutions to spread on an organic low-energy solid surface was related to the value of the solid and to the surface tension of the solution.nAbrupt changes in slope were found in all wettability curves of micelle-forming compounds. The discontinuities for both surfaces oc-curred at approximately equal concentrations for a given wetting agent and were essentially determined by a change in the adsorption at the solution/air interface and not at the solid/solution interface. The con-centrations at which the breaks in slope occurred were close to the reported critical micelle concentrations but were slightly lower.