Synthesis and surface activity properties of new gemini surfactants with hydroxyl group and piperazine ring

The reaction of 1,4-bis(2-hydroxypropyl)piperazine with alkyl bromides produced cationic gemini surfactants at a 1:2 molar ratio. Tensiometric, conductometric, and dynamic light scattering techniques were employed to measure the surface activity, specific electrical conductivity, and aggregate size of the obtained gemini surfactants, respectively. The critical micelle concentration, polar group cross-sectional area, maximum adsorption, surface pressure, degree of counterion association, and Gibbs free energy variations during micelle formation and adsorption processes were computed based on the obtained data. It was established how the length of the hydrophobic group in gemini surfactants affected their colloid-chemical characteristics. The antibacterial properties of these compounds were evaluated using the disk-diffusion method against various Gram-positive and Gram-negative bacteria, as well as fungi. Researchers also investigated the C12 chain gemini surfactant’s capacity to prevent corrosion of mild steel in a CO2-saturated NaCl solution. © 2025 Egyptian Petroleum Research Institute (EPRI). This is an open access article under the CC BY-NC-ND license https://creativecommons.org/licenses/by-nc-nd/4.0/.