Abstract: The adhesion tensions of surfactant solution/solid interface hare been measured by Wilhelmy method. The adsorptions of surfactants at L/S interface have been calculated from the adhesion tensions by applying Gibbs'equation and Young's equation. This method is preferable to the γ—θ method, since it would be more simple—only one quantity needed to be measured comparing to two quantities needed in γ-θ method, more exact—the concentration of solution would not be changed by adsorption, and better repeatability.[see Tab.1]
The systems composed of the aqueous solutions of C_(12)H_(25)SO_4Na, C_(16)N_(33)N(CH_3)_3Br and C_7F_(15)COONa and the solid of paraffin, polyTatraFluoroEthylene, Methylated Glass and polyMethyl Methacrylate have been investigated. Data of adhesionten sion indicate that the fluorocarbon surfactant will be better for improving the hydrophilicity of polytetrafluoroethylene. Than the hydrocarbon surfactants, and the hrdrocarbon surfactants show more effectiveness in making paraffin and methylated Glass hydrophilic. Here mutualphobicity between fluorocarbon andhydrooarbon chain was revealed once more. The order of saturated adsorptions of various surfactants on solids is Γ_(PTFE)>Γ_(PARAFFIN)>Γ_(M-G)>Γ_(PMMA). It just reverse thes order of the adhesion tensions of water/solid interfaces, which indicates the hydrophobicity of the solids.