抄録
The adsorbability of surface active agents at oil-water interfaces and the influence of various norganic electrolyte on it were investigated by making electrocapillary curves. The oil phase was the solution of tetrabutylammonium chloride in methylisobutylketone, and the aqueous phase contained anionic, cationic or nonionic surface active agents in addition to the inorganic electrolyte. It was found that the interfacial tension decreased over the anodic or cathodic polarization range, depending upon whether the surface active agent was anionic or cationic. This decrease was strongly influenced by the kind and concentration of the electolyte in the aqueous phase.
Linear relations held between the interfacial excess of the surface active agent and the cubic root of surface active agent concentration of the aqueous phase, as well as between the former and the cubic root of the ionic strength of the aqueous phase. These were in good agreement with Davies' equation derived theoretically. For alkylsulphate ions of various chain length, the free energy of desorption was calculated to be ca. 750 cal mol-1 for each -CH2- group.
