Application of Conductance Study to Analyze Micellization Behavior of Cationic Gemini Surfactants in Water and Water–Ethanol Solvent Mixed Media

Abstract

The paper presents the analysis of micellization behavior of cationic gemini surfactants with similar structures with varying atom number in spacer: heptylene-1,7-bis-(dimethyloctylammonium) bromide (8−7−8) and octylene-1,8bis(dimethyloctylammonium) bromide (8−8−8) in water and water−ethanol solvent mixed media. Experiments were carried out by using conductometric method within the temperature range of 288.15−323.15 K. The values of micellization parameters and thermodynamic functions of aggregation [critical micelle concentration (cmc), the degree of dissociation of micelles (α), enthalpy of micellization (ΔH m o ), entropy of micellization (ΔS m o ), Gibbs free energy of micellization (ΔG m o ] within the temperature range investigated were determined. Based on the investigations performed it has been shown that the systems containing the additives ethanol have a positive value ΔG trans o , a more positive value ΔG mo , and a higher value of α and cmc as compared to pure water what confirms that the micellization process is delayed. The less spontaneous micellization behavior was observed for the surfactant with odd number of carbon atoms in spacer: 8−7−8. In this case the value of cmc was higher than the nearest homologues with even number of carbon atoms in spacer (8−8−8 and 8− 6−8 surfactants). At higher temperatures, the differences in aggregation behavior became less visible.

Elucidation of Interactions between l‐Ascorbic Acid and Mixed Micellar Aggregates of Catanionic {Sodium Dodecylsulfate + Cetyltrimethylammonium Bromide} Surfactants via Physicochemical and Spectroscopic Studies

“…This may lead to the increase of ionic repulsions between the similarly charged head groups of surfactant molecules either in the cationic or in the anionic rich mixture of surfactants. Such observations have also been reported (Das et al, ; Harutyunyan and Markarian, ; Khan et al, ; Ludzik et al, ; Paria and Khilar, ) and explained by using the Debye length i.e ., the thickness of ionic atmosphere surrounding each ion in solution. Therefore, the lessening of the dielectric constant of the aqueous medium hinders the process of aggregation by reducing the hydrophobic interactions, and these facts support our above‐described results.…”

Antimicrobial and Cytotoxic Properties of Bisquaternary Ammonium Bromides of Different Spacer Length

“…All amphipilic compounds (8–6–8, 8–7–8, 8–8–8, 8–9–8) were synthesized according to the procedure previously reported (Łudzik et al, ). Some spectra of the compounds investigated are presented in Supporting Information (Fig.…”

“…For that reason, the use of the dimeric surfactants as main components in disinfectants seems to be a good solution. There are some scientific papers available on the antibacterial properties of different gemini surfactants (Colomer et al, ; He et al, ; Kuperkar et al, ; Zhang et al, ) and papers on thermodynamics of micellization of group of 8– s –8 (Łudzik, Kustrzepa, & Piekarski, ; Łudzik, Kustrzepa, Piekarski, & Jóźwiak, ), but so far, there is a lack of information about the antimicrobial properties and cytotoxicity of the surfactants of that group. In the present study, we investigated the antimicrobial activity and the long‐term antimicrobial activities of the aqueous solutions of alkyleno‐α,ω‐bis(dimethyloctylammonium) bromide surfactants (for s = 6, 7, 8, 9) against Gram‐positive S. aureus ( ATCC 6538) and Gram‐negative P. aeruginosa (ATCC 9027) stains, and common fungus C. albicans (ATCC 10231).…”

Aggregation‐Enhanced Emission of Fluorescent‐Gemini Surfactants with High Photostability for Cell‐Membrane Imaging

“…By introducing fluorescent blocks into surfactants, it is possible to investigate the aggregation behavior of surfactants using spectral analysis. Compared with traditional methods, such as surface tensiometry (Zhang et al, ), conductimetry (Łudzik, Kustrzepa, & Piekarski, ; Łudzik, Kustrzepa, Piekarski, & Jóźwiak, ), rheology (Lu, Huang, Li, Jia, & Fu, ), isothermal‐titration calorimetry (Li, Wettig, & Verrall, ), and dynamic‐light scattering (Cuenca, Falcone, Silber, & Correa, ), spectroscopy shows advantages. In fact, pyrene has been used to study micellar systems for a long time due to its sensitivity to microenvironments (Kalyanasundaram & Thomas, ).…”

“…Compared with traditional methods, such as surface tensiometry (Zhang et al, 2014), Electronic supplementary material The online version of this article (doi:10.1002/jsde.12036) contains supplementary material, which is available to authorized users. conductimetry (Łudzik, Kustrzepa, & Piekarski, 2014;Łudzik, Kustrzepa, Piekarski, & Jó zwiak, 2016), rheology (Lu, Huang, Li, Jia, & Fu, 2008), isothermal-titration calorimetry (Li, Wettig, & Verrall, 2004), and dynamic-light scattering (Cuenca, Falcone, Silber, & Correa, 2016), spectroscopy shows advantages. In fact, pyrene has been used to study micellar systems for a long time due to its sensitivity to microenvironments (Kalyanasundaram & Thomas, 1977).…”