Surface and antimicrobial properties of semi-fluorinated quaternary ammonium thiol surfactants potentially usable for Self-Assembled Monolayers

The surfactant and antimicrobial activities of thiol and disulfide derivatives containing a quaternary ammonium group bearing variable perfluorinated carbon chains via an amide connector between the sulfur and nitrogen atoms were evaluated with the future aim to be grafted on metal surfaces for obtaining contact-active and non-adhesive auto-biocidal surfaces. Their biostatic and bactericidal activities against four microbial strains (Pseudomonas aeruginosa, Staphylococcus aureus, Aspergillus niger and Candida albicans) were measured. The presence of the thiol, disulfide and amide functions in these surfactants were discussed in relation with antimicrobial activity along with the influence of the length of fluorinated chains in order to determine which molecular parameters are ‘critical’ for biological activity.