Modulation of aggregation behavior, antimicrobial properties and catalytic activity of piperidinium surfactants by modifying their head group with a polar fragment

To establish the effect of surfactants structure on their functional activity a number of alkyl-N-hydroxye thylpiperidinium bromides with different length of the hydrophobic tail were synthesized and characterized. Aggregation parameters of these surfactants were determined using tensiometry and fluorimetry. It was shown that the piperidinium surfactants, including those functionalized with OH groups, show a high antimicrobial effect at concentrations lower than critical micelle concentration for both bacteria and fungi, with the low hemolytic activity revealed. In addition, these surfactants were studied as micellar catalysts in alkaline hydrolysis of carboxylic acid esters. Micellar catalytic effect increases with an growth in the length of the alkyl tail, as well as with an increase in the number of hydroxy groups in surfactant molecule and can exceed two orders of magnitude. (C) 2021 Elsevier B.V. All rights reserved.