Adsorption and micellization behavior of synthesized amidoamine cationic surfactants and their biological activity

The adsorption and micellization behavior at aqueous surface of synthesized amido-amine cationic surfactants was studied using surface tension and conductometric measurements at three different temperatures of 25, 40 and 60 °C. The chemical structure of the synthesized cationic surfactants was confirmed using Fourier transform infrared and proton nuclear magnetic resonance spectroscopy. The synthetic route is simple and comprises two steps. The first is amidation between palmitic acid and dimethyl amino propyl amine, while the second step is quaternization of the first step product with different alkyl bromides. The study evaluated the effect of temperature and the hydrophobic chain length of the synthesized amidoamine cationic surfactants on the studied surface parameters. In aqueous system the adsorption tendency of the synthesized cationic surfactants is higher than micellization and both increase by increasing the hydrophobic character and the solution temperatures. The synthesized surfactants were found to have good antibiotic effect against gram positive and negative bacteria and fungi.