Surface, aggregation properties and antimicrobial activity of four novel thiourea-based non-ionic surfactants

Four novel thiourea-based non-ionic surfactants, 1-decanoyl-3-phenylthiourea, 1-decanoyl-3-ethylthiourea, 1-butyl-3-decanoylthiourea and 1-cyclohexyl-3-decanoylthiourea were synthesized from readily available synthetic building blocks in high yield. The compounds were characterized by 1H NMR, 13C NMR, FTIR and UV–Visible spectrophotometry. These surfactants show very low solubility in water, and interestingly low, but well-defined sub-millimolar critical micelle concentrations (CMCs) in ethanol and toluene, indicating that they are moderately amphiphobic. The antibacterial activity of the synthesized thiourea-based surfactants was tested against five bacterial strains, as well as the antifungal activity against five fungal strains. In all cases, the inhibition of bacterial and fungal growth was significant for all of the synthesized molecules. These molecules are particularly desirable for antimicrobial functionalization of surfaces due to their facile synthesis and their low water solubility, providing robust coatings in aqueous environments.