Mixed Micellization of Gemini Surfactant with Nonionic Surfactant in Aqueous Media: A Fluorometric Study (original) (raw)
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Studies of mixed micelle formation between cationic gemini and cationic conventional surfactants
Journal of Colloid and Interface Science, 2008
Mixed micellization of dimeric cationic surfactants tetramethylene-1,4-bis(hexadecyldimethylammonium bromide)(16-4-16), hexamethylene-1,6-bis(hexadecyldimethylammonium bromide) (16-6-16) with monomeric cationic surfactants hexadecyltrimethylammonium bromide (CTAB), cetylpyridinium bromide (CPB), cetylpyridinium chloride (CPC), and tetradecyltrimethylammonium bromide (TTAB) have been studied by conductivity and steady-state fluorescence quenching techniques. The behavior of mixed systems, their compositions, and activities of the components have been analyzed in the light of Rubingh's regular solution theory. The results indicate synergism in the binary mixtures. Ideal and experimental critical micelle concentrations (i.e., cmc * and cmc) show nonideality, which is confirmed by β values and activity coefficients. The micelle aggregation numbers (N agg), evaluated using steady-state fluorescence quenching at a total concentration of 2 mM for CTAB/16-4-16 or 16-6-16 and 5 mM for TTAB/16-4-16 or 16-6-16 systems, indicate that the contribution of conventional surfactants was always more than that of the geminis. The micropolarity, dielectric constant and binding constants (K sv) of mixed systems have also been evaluated from the ratios of respective peak intensities (I 1 /I 3 or I 0 /I 1).
Journal of Molecular Liquids, 2014
In the present study, the influence of the hydrocarbon chain length of gemini surfactants on the process of micellization in mixed surfactant systems was investigated. Experiments were carried out with alkyldiyl-α, ω-bis(tetradecyldimethylammonium bromide) (m-4-m) dicationic gemini (m = 14, 16)/anionic sodium dodecylbenzene sulfonate (SDBS) mixed surfactant systems in different ratios. The critical micelle concentration (cmc) values of binary mixtures of surfactants were evaluated using surface tension measurements. Results showed that mixtures of the SDBS with gemini surfactants possessed significant deviations from ideal behavior (attractive interactions). The application of the regular solution theory (RST) to experimental data yielded the interaction parameter at mixed micelles (β) and air-water interface (β σ), indicating an attractive interaction and reflecting the synergistic behavior in both the systems. The experimental mole fraction (X 1) was found to be lower than the ideal mole fraction (X 1 ideal), the mole fractions of SDBS for both systems, provided that mixed micelles were more occupied by SDBS. In addition, the micelle aggregation number (N agg) increased with an increase in the length of the hydrophobic tail. The micropolarity and binding constant (K sv) values of various combinations were determined from the ratio of intensity (I 1 /I 3) of peaks of pyrene fluorescence emission spectrum and its quenching.
Mixed Micellization Properties of Cationic Monomeric and Gemini Surfactants
Mixed micellization properties of the cationic monomeric surfactants hexadecyltrimethylammonium bromide (CTAB), hexadecyltriphenylphosphonium bromide (CTPB), hexadecyltributylphosphonium bromide (CT-BuPB), and tetradecyltriphenylphosphonium bromide (TTPB) with gemini surfactant C 16 H 33 (CH 2 ) 2 N + -(CH 2 ) 10 N + (CH 2 ) 2 C 16 H 33 · 2Br -(C 16 -10-C 16 · 2Br -) have been investigated by performing conductivity measurements in aqueous solution. The conductance data were used to obtain the values of the critical micelle concentration (cmc) of mixed surfactant systems having different compositions. The mixed cmc values determined from the experimental data were used to calculate the interaction parameter ( ) using regular solution theory for the mixed surfactant system. The cmc values show nonideality, and the negative values of indicate an overall attractive force in the mixed state. Also, the measured values of the excess free energy of mixing have negative values for all of the systems. † Part of the "Sir John S. Rowlinson Festschrift".
The Journal of Physical Chemistry B, 2007
The micellization of anionic gemini surfactant, N, N′-ethylene(bis(sodium N-dodecanoyl--alaninate)) (212), and its monomer, N-dodecanoyl-N-methyl alaninate (SDMA), and polyethoxylated nonionic surfactants, C 12 E 5 and C 12 E 8 , has been studied tensiometrically in pure and mixed states in an aqueous solution of 0.1 M NaCl at pH 11 to determine physicochemical properties such as critical micellar concentration (cmc), surface tension at the cmc (γ cmc ), maximum surface excess (Γ max ) and minimum area per surfactant molecule at the air/water interface (A min ). The theories of Rosen, Rubingh, Motomura, Maeda, and Nagarajan have been applied to investigate the interaction between those surfactants at the interface and in the micellar solution, the composition of the aggregates formed, the theoretical cmc in pure and mixed states, and the structural parameters as proposed by Tanford and Israelachvili. Various thermodynamic parameters (free energy of micellization and interfacial adsorption) have been calculated with the help of regular solution theory and the pseudophase model for micellization.
Interaction Between Cationic Gemini and Monomeric Surfactants: Micellar and Surface Properties
Attraction effects in the mixed micelle of gemini (C 16 -12-C 16 , 2Br − and monomeric surfactants i.e., cetyltrimethylammonium bromide (CTAB), cetyltriphenylphosphonium bromide (CTPB) and cetyltributylphosphonium bromide (CTBuPB) mixtures in aqueous solution were investigated by conductivity and surface tension measurements. The attractive interaction of surfactants in the mixed micelle leading to non-ideality has been theoretically treated by Clint's and Rubingh's model in the light of regular solution theory. The experimental critical micelle concentration (cmc) values were lower than predicted from ideal mixture theory. The negative values of interaction parameters ( m and for mixed micelle formation indicate the attractive interaction for all the systems. The Motomura's theory was used to determine the composition of each compound in mixed micelles (X ideal . The excess free energy of the mixed systems was also calculated and the obtained negative values for all the mixed systems studied gave an indication that the mixed micelles are thermodynamically more stable relative to the individual component.
The surface properties and mixed micellization behavior of binary combinations of cationic gemini (C 16 -4-C 16 , 2Br − ) tetramethylene-1,4-bis(cetyldimethylammonium bromide) with cationic monomeric surfactants viz. cetyltriphenylphosphonium bromide (CTPB), tetradecyltriphenylphosphonium bromide (TTPB), cetyltributylphosphonium bromide (CTBuPB), cetyldiethylethanolammonium bromide (CDEEAB) and tetradecyldiethylethanolammonium bromide (TDEEAB) have been investigated by surface tension and conductivity measurements in (10%, v/v) ethylene glycol mixture at 300 K. The critical micelle concentration (cmc), surface properties, max (maximum surface excess), A min (minimum surface area per molecule) and cmc (surface pressure at the cmc) have been determined. The deviation from the ideal of the mixed micelles has been discussed on the basis of Clint theory. The results of the mixed systems were analyzed in the light of the regular solution theory (Rubingh) and Rosen's theory to evaluate the composition of the mixed micelle, the activity coefficient, the interfacial mole fraction of the surfactant at the mixed adsorbed film and the corresponding interaction parameters (ˇandˇ). The negative values of interaction parameters (ˇandˇ) for mixed micelle formation indicate the attractive interaction for all the system. The standard Gibbs free energies of adsorption ( G • ads ), standard Gibbs free energies of micellization ( G • m ), the excess free energies of micellization ( G ex ) and minimum free energy of the surface ( G (s) min ) of gemini with cationic monomeric surfactants were also evaluated. The G • ads , G • m and G ex values are negative indicating the spontaneity and stability of the mixed micelle.
Journal of Chemical & Engineering Data, 2010
The mixed micellar properties of two cationic gemini surfactants, alkanediyl-R,ω-bis(tetradecyldimethylammonium bromide) and alkanediyl-R,ω-bis(hexadecyldimethylammonium bromide), 14-s-14 and 16-s-16, in aqueous solution have been investigated by conductivity and fluorescence techniques. The conductivity method has been carried out to evaluate critical micelle concentration (c), degree of counterion binding (g), and other related parameters like ideal mixed critical micelle concentration (c*), micellar mole fraction (x), interaction parameter () from Rubingh's model, and x ideal from Motomura's model. Activity coefficients (f 1 and f 2) and Gibbs excess energy (G E) were also calculated. Fluorescence measurements were used to obtain the values of N agg and Stern-Volmer constant (K sv). The results suggest synergism in the system. The values are negative, and their magnitudes increase with increasing spacer chain lengths. x 1 > x 1 ideal values suggest that the contribution of the 14-s-14 component is greater as compared to that in the ideal state.
Journal of Colloid and Interface Science, 2009
Mixed micellization and surface properties of binary mixtures of cationic gemini surfactant butanediylα,ω-bis(dimethylcetylammonium bromide) (G4, 16-4-16) with conventional surfactants cetylpyridinium chloride (CPC), sodium bis(2-ethylhexyl)sulfosuccinate (AOT), and polyoxyethylene 10 cetyl ether (Brij56) have been studied using conductometric and tensiometric methods. To explain and compare the results theoretical models of Rubingh, Rosen, Clint, and Maeda have been used to obtain the interaction parameter, minimum area per molecule, surface excess, mixed micelle composition, free energies of micellization and adsorption, and activity coefficients. The activity coefficients and experimental critical micelle concentration (cmc) values are less than unity indicating synergism in micelles as well as at interface. Also, expansion of the minimum area per molecule was observed in the binary systems supported by low values of packing parameter.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2011
The mixed surfactant systems of anionic sodium dodecyl trioxyethylene sulfate (SDES) and gemini surfactants (cationic) of the series N,N'-bis-(dimethyldodecyl)-˛,ω-dialkanediammoniumdibromide, 12-s-12 (s = 2, 4, 6) at different molar ratios were studied by surface tension measurements of aqueous solution as a function of total concentration under standard condition. Various parameters like critical micelle concentration (CMC), surface excess concentration (max), minimum area per molecule (A min), interaction parameter of mixed micelle and adsorption monolayer (ˇm, ˇo) as well as thermodynamic and micellar properties have been determined using Clint, Rubingh, Maeda and Rosen approach. The strong interaction showing very low CMC and large negative interaction parameter ˇ were due to weakening of the electrostatic head group repulsion which favors the mixed micelle formation. The results are discussed in terms of the structural characteristics and spacer chain of gemini surfactants and also in terms of the presence of EO group in SDES molecule. Gemini surfactants bind tightly with SDES by electrostatic, hydrophobic and ion-dipole interactions. Thermodynamic parameters for all three cationic-anionic mixed systems were evaluated. From excess free energy of micellization we can conclude that thermodynamically stable micelles are formed with strong synergistic interaction.
Journal of Molecular Liquids, 2017
In this paper, we have studied the mixed surfactant systems containing a cationic gemini surfactant N,N'-bis(dimethyldodecyl)-1,2-pentanediammonium dibromide (12-5-12) with several differently charged surfactants (cationic/anionic/non-ionic/zwitterionic) by using surface tension, small angle neutron scattering (SANS) under standard condition. All the surfactants have same dodecyl chain but different in polar head group viz. Sodium dodecyl trioxyethylene sulphate (SDES)(anionic), dodecyl trimethyl ammonium bromide (DTAB) (cationic), 3-[dodecyldimethyl ammonio] propane sulphonate (C12-PS)(zwitterionic), hexaethylene glycol monododecyl ether (C12E6)(non-ionic) and dimethyl dodecyl amine oxide (DMDAO) (cationic-non-ionic). The Clint, Rubingh, Maeda and Rosen approaches were employed to determine various parameters like critical micelles concentration (CMC), surface excess concentration (Гmax), surface pressure at CMC (πCMC), minimum area per molecule (Amin) etc. as well as thermodynamic parameters. Solubilization of some polycyclic aromatic hydrocarbons (PAHs) have done in single as well as in mixed surfactant systems. Order of solubilization capacity of PAHs compounds are different in pure/mixed surfactant micelles. The solubilization efficiency towards naphthalene, anthracene, and pyrene were measured and the molar solubilization ratio (MSR), deviation ratio (R) and micelle-water partition coefficient (km) were evaluated for single and mixed systems. Highlights Micellar properties have been determined using diffrent approach. The β parameters were negative, indicating strong synergistic interaction. Solubilization of some PAHs have done in single and mixed surfactant systems.