Surface properties and premicellar aggregation behavior of cationic gemini surfactants with mono- and di-(2-hydroxypropyl)ammonium head groups

Novel cationic gemini surfactants - pentanediyl-1,5-bis[mono(2-hydroxypropyl) alkylammonium] dibromide and pentanediyl-1,5-bis[di(2-hydroxypropyl) alkylammonium] dibromide {in the abbreviation form - CnC5Cn[iso-Pr(OH)] and CnC5Cn[iso-Pr(OH)]2; alkyl - CnH2n+1 with n = 8, 9, 12 and 16} were synthesized. Surface tension, electroconductivity and dynamic light scattering methods were applied to study aggregation properties of these surfactants in aqueous medium. By tensiometric method it was established that, at two studied concentrations in water, the synthesized gemini surfactants form aggregates. This occurs well below the critical micelle concentrations (CMC) of these surfactants. The influence of the length of the surfactants alkyl chain and the number of the 2-hydroxypropyl fragments in the head group on the surface activity parameters and binding degree of the counterion has been studied. By dynamic light scattering method, the impact of the number of the 2-hydroxypropyl groups in the gemini surfactants with C12–chain on the micelles sizes at the concentrations higher than CMC has been investigated. It was revealed that the synthesized surfactants possess an antimicrobial property. © 2019 Elsevier B.V

Micellization and antimicrobial properties of N-alkyl-(2-hydroxypropyl)morpholinium bromides

New ionic-liquid cationic surfactants have been synthesized on the basis of alkyl (C9, C10, C12, C14) bromides and 1-(4-morpholinyl)-2-propanol. Surface activity and specific electroconductivity of aqueous solutions of the obtained surfactants have been studied by tensiometric and conductometric methods. Depending on the length of the alkyl chain, the values of critical micellization concentration (CMC), maximum adsorption (Гmax), area of minimal cross-sectional surface of polar group of the surfactant (Amin), adsorption efficiency (pC20), surface pressure (πCMC), binding degree of the counter-ion (β), changes of Gibbs free energies of micellization and adsorption processes (ΔGmic and ΔGad) have been determined. Antimicrobial properties of the synthesized ionic-liquid surfactants have been studied on the example of different bacteria and fungus. © 2021 Elsevier B.V

Effects of head group on the properties of cationic surfactants containing hydroxyethyl- and hydroxyisopropyl fragments

Cationic surfactants containing different head-groups have been synthesized by interaction of tetradecyl bromide and amines having hydroxyalkyl group (monoethanolamine, diethanolamine, triethanolamine, methylethanolamine, methyldiethanolamine, diethanolisopropanolamine, ethanoldiisopropanolamine, triisopropanolamine). Surfactivity parameters of the synthesized cationic surfactants have been determined by measurements of surface tension and electroconductance. The character of change of the colloidal-chemical parameters with an increase of the number of hydroxyethyl and hydroxyisopropyl groups in the head-group of the cationic surfactants has been established. The synthesized cationic surfactants possess effective antibacterial and antifungal properties. © 2018 Elsevier B.V