Interaction of novel anionic gemini surfactants with cetyltrimethylammonium bromide.

This study describes the synthesis of three novel anionic gemini surfactants via a convenient and easily controllable method, sodium 2,2'-(6,6'-(ethane-1,2-diylbis(azanediyl) bis(4-(octylamino)-1,3,5-triazine -6,2-diyl) bis(azanediyl)diethanesulfonate (C(8)-2-C(8)), sodium 2,2'-(6,6'-(propane-1,3-diylbis(azanediyl) bis(4-(octylamino)-1,3,5-triazine-6,2-diyl) bis(azanediyl)diethanesulfonate (C(8)-3-C(8)), sodium 2,2'-(6,6'-(butane-1,4-diylbis(azanediyl) bis(4-(octylamino)-1,3,5-triazine-6,2-diyl) bis(azanediyl)diethanesulfonate (C(8)-4-C(8)). The interactions of these new anionic gemini surfactants with the conventional cationic cetyltrimethylammonium bromide (CTAB) are investigated in 0.1 mol/L NaCl aqueous solutions. The mixed systems are C(8)-2-C(8)/CTAB, C(8)-3-C(8)/CTAB, and C(8)-4-C(8)/CTAB, and the mole factions (alpha(G)) of C(8)-n-C(8) (n=2, 3, 4) were 0.5, 0.7, and 0.9 respectively. These mixtures exhibit synergism in both surface tension reduction effectiveness and surface tension reduction efficiency. When alpha(G)=0.5 the three systems exhibit synergism in mixed micelle formation, whereas the other surfactant mixtures do not show this synergism. The interactions in mixed adsorbed films are stronger than those involved in mixed micelles for all mixtures.