Synthesis, surface, biological activity and mixed micellar phase properties of some biodegradable gemini cationic surfactants containing oxycarbonyl groups in the lipophilic part

Three biodegradable gemini cationic surfactants were synthesized and namely: N,N′-bis(2-hydroxyethyl)-N,N′-dimethyl-N,N′-bis(2-(tetradecanoyloxy) ethyl)ethane-1,2-diaminium bromide; N,N′-bis(2-hydroxyethyl)-N,N′-dimethyl-N,N′-bis(2-(tetradecanoyloxy) ethyl) hexane-1,6-diaminium bromide and N,N′-bis(2-hydroxyethyl)-N,N′-dimethyl-N,N′-bis(2-(tetradecanoyloxy) ethyl)dodecane-1,12-diaminium bromide. The chemical structures of these compounds were characterized by FTIR, 1H NMR and elemental analysis spectroscopy. The surface parameter including: the critical micelle concentration (CMC), effectiveness (πcmc), efficiency (Pc20), maximum surface excess (Γmax) and minimum surface area (Amin), were calculated from it is surface tension measurements. The synthesized surfactants showed higher surface activity. The thermodynamic parameters showed that adsorption and micellization processes are spontaneous. It is clear that the synthesized surfactants showed their tendency towards adsorption at the interfaces and also micellization in the bulk of their solutions. The synthesized compounds were applied on the field of biocide via measuring there efficiency against different strain of pathogenic bacteria and fungi as well as sulfate reducing bacteria using inhibition zone diameters method and minimum inhibition concentration values. The synthesized compounds showed good antimicrobial activities against the tested microorganisms including Gram positive, Gram negative and fungi as well as sulfate reducing bacteria. The biodegradability of the synthesized surfactants was tested in river water using Die-away method and showed their readily biodegradation in the open environment. The CMC of mixtures in equal mole fraction (G2 + G6 (5:5), G2 + G12 (5:5), G6 + G12 (5:5)) and the CMC of mixtures was compared with pure gemini surfactants. Also the mixed micellization parameters were calculated.