表面活性剂在低能固体表面上的吸附——Ⅱ. 粘附张力法研究碳氟与碳氢表面活性剂的吸附

研究了直接测定粘附张力、推算表面活性剂在低能固体表面上吸附的方法。与文献结果比较, 说明此法可行, 且较γ-θ法~4]方便、准确、重复性好。研究了C_(12)H_(25)-SO_4Na、C_(16)H_(33)N(CH_3)_3Br、C_7F_(15)COONa水溶液与聚四氟乙烯、石蜡、甲基化玻璃、聚甲基丙烯酸甲醋界面上的粘附张力及吸附, 结果表明: (1)各种表面活性剂在四种固体上的饱和吸附量顺序皆为~ΓPTFE>~ΓAE>~ΓMG>~ΓPMMA与各固体对水粘附张力增加的顺序相同; (2)改善固体亲水性的能力, 对于碳氟固体, 碳氟表面活性剂优于碳氢表面活性剂, 对于碳氢固体则相反。

INVESTIGATION OF SURFACTANTS ADSORPTION ON LOW-ENERGY SOLID SURFACE Ⅱ. BY THE ADHESION TENSION METHOD——THE ADSORPTION OF HYDROCARBON AND FLUOROCARBON SURFACTANTS

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.