Synthesis and evaluation of micellar properties and antimicrobial activities of imidazole-based surfactants

The synthesis of two types of imidazole-based surfactants, [(ROCOCH(2)MIm)Br] and [(RNHCOCH(2)MIm)Br], of varying chain lengths (C-10, C-12 and C-16), was conducted in the present work. The synthesis involves an initial reaction of bromoacetic acid with fatty alcohols or fatty amines, followed by quaternization with IN-methyl imidazole. The micellar properties of all the synthesized compounds were determined using surface tensiometry and compared with [(RMIm)Br], a well-studied alkyl-substituted imidazole-based surfactant. Within the same homologous series, a decrease in critical micelle concentration (cmc) was observed with increasing alkyl chain length in all three types of cationic surfactants. Introduction of an ester [(ROCOCH(2)MIm)Br] or an amide group [(RNHCOCH(2)MIm)Br] in the alkyl chain lowers the cmc when compared to a cationic surfactant without functional group, [(RMIm)Br]. The synthesized surfactants were also assayed for antimicrobial activities and found to possess good activities against selected strains.