Synthesis, Characterization and Solution Properties of Novel Cationic Ester-Based Gemini Surfactants

Abstract

Abstract The present investigation involves the synthesis of a series of novel green ethylene oxide-linked diester-functionalized cationic gemini surfactants 2,2′-[(oxybis(ethane-1,2-diyl))bis(oxy)]bis(N-alkyl-N,N-dimethyl-2-oxoethanaminium) dichloride (C m -DEG-C m ; m = 12, 14, 16). These compounds were characterized by 1 H-NMR, MS-ESI (+), FT-IR spectroscopy and elemental analysis; their solution properties were evaluated by surface tension and rheology measurements. The dimeric surfactant, C m -DEG-C m , possesses improved physicochemical properties as compared to its monomeric counterpart. Much lower critical micelle concentration ( cmc ) makes the cationic gemini surfactants more useful for the biomedical, pharmaceutical, industrial and academic sectors. Longer the alkyl chain of surfactants lower are the cmc values, the order is C 16 -DEG-C 16 < C 14 -DEG-C 14 < C 12 -DEG-C 12 . For all the three synthesized gemini surfactants no cloud point was noticed in between the temperatures 0 °C to 100 °C at the concentrations 0.002 mM, 0.02 mM and 0.2 mM of the aqueous surfactant solutions which is a beneficial factor for the use of these amphiphiles in various areas of application.