Symmetric and Dissymmetric Pseudo-gemini Amphiphiles Based on Propoxylated Ethyl Piperazine and Fatty Acids

Novel symmetric and dissymmetric pseudo-gemini surfactants are synthesized using ethylpiperazine, propylene oxide and six different fatty acids (capric, lauric, myristic, palmitic, stearic, oleic) as starting materials. The synthesis follows a simple pathway excluding heating or catalyst. Important surface activity properties including critical micelle concentration (CMC), surface tension at CMC (gamma CMC), surface pressure at CMC (pi CMC), negative logarithm of concentration to achieve 20 mN/m reduction in surface tension (pC20), minimum area at interface (Amin) and maximum surface excess concentration (Gamma max) are obtained through surface tension and electrolytic conductivity measurements. Antimicrobial properties of the synthesized amphiphiles are evaluated using disk diffusion method and are compared to those of standard antibiotic agents. Particle size distribution patterns are obtained using dynamic light scattering (DLS). This work investigates the effect of dissymmetry on various surface activity and antimicrobial properties. Dissymmetric pseudo-gemini amphiphiles have a few times higher CMC compared to analogous symmetric surfactants. However, better antimicrobial properties are observed when there is some dissymmetry between hydrophobic groups. In this work we report the synthesis of symmetric and dissymmetric pseudo-gemini amphiphilic structures employing an economically feasible reaction pathway using ethyl piperazine, propylene oxide and fatty acids as starting materials. Surface activity parameters of the aqueous solutions of the amphiphiles were tested. Antimicrobial properties were evaluated.image