A series of cationic gemini surfactants, N,N′-bis­(alkyl)-N,N′-bis­(2-hydroxypropyl)­ethylenediammonium dibromide, [C n H2n+1(CH3CH­(OH)­CH2)­NH­(CH2)2NH­(CH2CH­(OH)­CH3)­C n H2n+1]­Br2 (where n is the tail chain length, n = 9, 12, and 14), referred to as C n C2C n [iso-Pr­(OH)] was synthesized. Via conductometric and tensiometric methods, at different temperatures (283 to 313 K), specific electrical conductivities and surface tensions of the aqueous solutions of these cationic gemini surfactants were determined. According to the obtained values, micellization and adsorption parameters such as critical micellization concentration (CMC), maximum surface excess (Γmax), minimal cross sectional surface area of surfactant polar group (A min), adsorption efficiency (pC20), surface pressure (π), and binding degree of counterion (β) were calculated. The values of standard Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) were also computed. Via the dynamic light scattering method, diameters of aggregates of the synthesized cationic gemini surfactants were determined in water. It was established that the diameters of these aggregates decrease with a temperature rise. Antibacterial properties of the synthesized cationic surfactants against sulfate-reducing bacteria (SRB) were studied.

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Two new classes of gemini cationic surfactantshexanediyl-1,6-bis[(isopropylol) alkylammonium] dibromide {in the abbreviation form: C n C 6 C n [iPr-OH] and C n C 6 C n [iPr-OH] 2 ; alkyl: C n H 2n + 1 with n = 9, 10, 12 and 14}-have been synthesized by interaction of alkyl bromides with N,N 0 -di-(isopropylol)-1,6-diaminohexane and N,N,N 0 ,N 0 -tetra-(isopropylol)-1,6-diaminohexane. The surface tension, electrical conductivity, and dynamic light scattering (DLS) techniques were used to investigate the aggregation properties of the gemini cationic surfactants in aqueous solution. The formation of critical aggregates at two concentrations in an aqueous solution from obtained gemini cationic surfactants were determined via the tensiometric method. Thus, these gemini cationic surfactants start to form aggregates at concentrations well below their critical micelle concentrations (CMC). The surface properties and the binding degree (β) of the opposite ion were tested against the length of the surfactant hydrocarbon chain and the number of the isopropylol groups in the head group. By applying the DLS technique, it was explored that how the number of isopropylol groups in gemini cationic surfactants with C 12 H 25 chain affects the sizes of micelles at concentrations greater than CMC. It was discovered that the obtained gemini cationic surfactants have a biocidal character.