THE EFFECT OF THE STRUCTURE OF SURFACE-ACTIVE QUATERNARY AMMONIUM-SALTS ON ADSORPTION AND WETTING

Wetting of glass and Teflon in air and in a dodecane medium by aqueous solutions of N,N'-bis(N-dodecyl-N,N-dimethyl)-1, 2-diammoniumethane d ibromide (DDADB) was studied. The structure of the DDADB adsorption la yers at the surfactant solution-air, solution-Teflon, and solution-gla ss interfaces was studied: the maximum adsorption, area per molecule, and length of a molecule in a saturated monolayer were determined. The results were compared with wetting and adsorption characteristics of hexadecyltrimethylammonium bromide (CTAB) solutions. The adsorption of DDADB at the surfactant solution-Teflon and solution-air interfaces w as shown to exceed that of CTAB. In contrast, the adsorption layer of DDADB on glass is more rarefied and has a weaker hydrophobic effect on the surface in comparison with CTAB.