Benzene ring containing cationic gemini surfactants: Synthesis, surface properties and antibacterial activity

New quaternary ammonium gemini surfactants of the general formula CnH2n+1-Ph-NHCOCH2N+(CH3)(2)-(CH2)(s)- N+(CH3)(2)CH2CONH-Ph-CnH2n+1 (with n = 8, 10,12, 14,16 and s = 2,4, 6) have been synthesized by an efficient synthetic pathway based on the quaternization of N,N,N',N'-tetramethylalkylenediamine with 2-bromo-N-(4-(alkyloxy) phenyl) acetamides. Their surface properties were investigated by surface tension, electrical conductivity and dynamic light scattering (DLS) measurements. The study shows that the incorporation of a benzene ring in the hydrophobic tail prompts micelle formation which leads to a smaller cmc values in the range of 0.21-0.009 mM compared to analogous geminis bearing alkyl hydrophobic chains. The length of the spacer and the hydrophobic chain has a pronounced effect on the aggregation behavior of surfactants molecules. This was confirmed by the average surfaces occupied by these molecules at the water-air interface calculated from the Gibbs equation. The size of the aggregates was measured by employing dynamic light scattering technique. The antimicrobial activity of investigated surfactants was evaluated against three microorganisms: Staphylococcus aureus, Escherichia coli and Candida albicans. (C) 2017 Elsevier B.V. All rights reserved.