Conventional Monomeric Surfactant Research Articles

New long tail gemini surfactant in aqueous solution: Self-assembly, rheological properties and responsiveness to hydrocarbon

Gemini surfactants are promising to replace conventional monomeric surfactants in various applications. In this paper, a new gemini surfactant with long unsaturated oleyl tails and bis(hydroxyethyl) ammonium head groups linked by butyl spacer was synthesized. Its critical micelle concentration in salt-free water (12 µM) is much lower than for its monomeric analog (220 µM). Without any additives this surfactant can form viscoelastic solutions with the viscosity of up to 1 kPa·s and elastic modulus of 15 Pa at the conditions, when the viscosity of the single-chained monomeric analog is close to that of pure water. These are one of the highest values reported so far for C18-tailed gemini surfactants without additives. The structure of the gemini surfactant solutions was studied by cryo-TEM and SAXS. Cryo-TEM revealed the presence of closed-looped micelles coexisting with linear wormlike micelles as well as the regular spacing between the micelles arising from strong electrostatic repulsion between them. The SAXS curves were well-fitted by a form-factor of core–shell cylinder, which yielded the radius of the core and the thickness of the shell equal to 1.4 nm each. Addition of n-decane induced the drop of viscosity by 6 orders of magnitude accompanied by the transformation of wormlike micelles into microemulsion droplets with 4.4 nm radius. Such gemini surfactants providing high viscoelasticity to aqueous solution that is responsive to added hydrocarbon are promising for the application in oil recovery as thickeners of fracturing fluids that can be cleaned up without any breakers at the backflow of oil.

Synthesis and application of novel Gemini esterquats in fabric softeners: Role of spacer chain length on surfactant properties

AbstractGemini surfactants are dimeric molecules having two monomeric units connected by a spacer. Gemini surfactants, owing to their molecular structure have better surfactant properties than other monomeric surfactants. Esterquat class gemini surfactants can be synthesized using a spacer containing ester linkages. In the current study, the synthesis of novel esterquat gemini surfactants was carried out with spacers of varying chain lengths and was characterized using sophisticated instrumental methods. Various surfactant properties including foaming, emulsification, CMC, surface excess, antimicrobial activity and wetting potential using contact angle were analyzed and compared with benzalkonium chloride. It was observed that the CMC as low as 24.79 × 10−3 mM of the synthesized surfactants is potentially lower than that of conventional monomeric surfactants and was found to increase with an increase in spacer chain length. Further, the applicability and evaluation of performance properties of the synthesized surfactants were studied in fabric softener formulation. The water absorbency and whiteness retention of the formulation prepared using 12‐6‐12 GS was the highest due to its better wettability amongst other synthesized surfactants owing to its higher spacer chain length. To summarize, the surface and anti‐microbial properties of the synthesized surfactants vary greatly with the alteration in spacer chain length.

Linear- and star-type quaternary ammonium salt-based trimeric surfactants: Effect of structure on adsorption and aggregation properties

Oligomeric surfactants with multiple hydrophobic and hydrophilic groups are an attractive novel surfactant with improved properties and functionalities compared with those of conventional monomeric surfactants. In this study, linear- and star-type quaternary ammonium salt-based trimeric surfactants, 3Cnlin-s-Q and 3Cntris-s-Q, were synthesized with different alkyl chain lengths (n), spacer chain lengths (s), and spacer skeletons (linear or star) and their adsorption and aggregation properties were characterized by electrical conductivity, surface tension, fluorescence, viscosity, dynamic light scattering (DLS), and small-angle X-ray scattering (SAXS). Trimeric surfactants exhibited high water solubility despite containing three alkyl chains. Conversely, the linear-type trimeric surfactant 3C14lin-3-Q, composed of rigid short spacer chains and long alkyl chains, exhibited low water solubility. The adsorption and orientation of trimeric surfactants at the air/water interface depended on the alkyl chain length, spacer chain length, and spacer skeleton, and the effect of alkyl chain length was dominant. The star-type trimeric surfactant 3C12tris-6-Q was efficiently adsorbed and oriented at the air/water interface, despite its long spacer and bulky skeleton, which extended from the center of the amino group in the spacer. Therefore, trimeric surfactants with high performance and advanced functionalities were successfully achieved. This study provides insights into the molecular design and synthesis of trimeric surfactants for future application in various industrial fields.

Iron ore production using a new Gemini surfactant at 273 K.

Herein we present the use of a Gemini surfactant and reverse froth flotation to efficiently separate magnetite from quartz and produce iron ore at 273 K. This surfactant achieved an obviously superior flotation performance (TFe recovery increased by 48.18%), and the dosage of the Gemini surfactant was three times less than that of a conventional monomeric surfactant. Our findings are expected to serve as a general guide to design a new and excellent collector for high-efficiency mineral flotation and to lead to an efficient and clean development of mineral resources.

Two new cationic Gemini surfactants: synthesis, surface activity, and applicability as a corrosion inhibitor

Two novel cationic Gemini surfactants (2C n GeQS, n = 12, 18) was designed and prepared via amidation and quaternization reaction. The molecular structure of the 2C n GeQS was confirmed by FTIR, 1H NMR and elemental analysis. The critical micelle concentration (CMC) of aqueous solutions of these surfactants was determined by surface tension measurements, and the surface activity parameter, such as effectiveness (π CMC), efficiency (pC 20), critical micelle concentration (CMC), maximum surface excess (Г max), minimum surface area (A min), were obtained. The results showed that 2C n GeQS have a higher surface activity than conventional monomeric surfactant. The CMC decreases with an increment in hydrophobic chain length, however, the surface tension at the cmc (γ CMC) shows the opposite trend. The thermodynamic parameters indicate that both micellization and adsorption processes of 2C n GeQS were spontaneous. In addition, the results obtained from weight loss measurements show that 2C n GeQS exhibits a greater protective effect than that of DTAB; inhibition efficiency (ηw%) of 2C12GeQS, 2C18GeQS%, and DTAB is 95.6%, 96.86%, and 52.8% for A3 carbon steel at 1 × 10−3 M.

Characteristic and Application of Anionic Dimeric Surfactants: A Review

AbstractAnionic dimeric surfactants have attracted much interest compared to the conventional monomeric surfactants. These surfactants have low critical micellar concentrations and an excellent ability in reducing the surface tension of water than conventional surfactants. Therewith, they also show better solubilizing and foaming properties, and a magnificent mildness to the skin. These special features may make them potentially attractive in several applications, for example, laundry detergents, cosmetics and personal care. This article describes the micellization and mixed micellization properties, performance properties, application and biodegradability of anionic dimeric surfactants.

Utilization of a new Gemini surfactant as the collector for the reverse froth flotation of phosphate ore in sustainable production of phosphate fertilizer

An effective collector plays a vital role in the reverse flotation of phosphate ore as well as sustainable production of phosphate fertilizer. Phosphate fertilizer is used to achieve the sustainable increase in the production of food. Phosphate ore is concentrated by reverse froth flotation and used as a raw material to produce phosphate fertilizer in industry. However, all the surfactants used in the phosphate ore reverse flotation process are conventional monomeric surfactants contain a single similar hydrophobic group in the molecule, which results in a low production efficiency and severe environmental contamination. In this work, a novel Gemini surfactant, N,N′-bis(dodecyldimethyl)-1,4-butane diammonium dibromide (BDBD) was prepared, and originally recommended as a collector for reverse froth flotation separation of silicoide from phosphate ore. The performance of BDBD was compared with the results acquired using its conventional monomeric surfactant dodecylamine hydrochloride (DAH). The bench-scale flotation results showed that BDBD had excellent collecting power for silicoide and significant selectivity against apatite at pH 9. Moreover, BDBD presented stronger desilication efficiency than DAH. Achieving the superior flotation performance (P2O5 recovery increased by 2.41%, P2O5 content increased by 0.26%, and SiO2 content reduced by 2.52%), the dosage of Gemini type BDBD collector (100 g/t) is four times less than that of monomeric DAH collector (400 g/t). Therefore, this work provides a promising approach to the sustainable phosphate fertilizer production and to address global food security concerns.

Gemini surfactant: A novel flotation collector for harvesting of microalgae by froth flotation

Froth flotation has been proved to be a promising approach for commercial scale harvesting of microalgae. However, all the surfactants used in the microalgae flotation harvesting process are conventional monomeric surfactants contain a single similar hydrophobic group in the molecule, which results in a low harvesting efficiency. In this work, a novel Gemini surfactant, N,N′-bis(cetyldimethyl)-1,4-butane diammonium dibromide (BCBD) was prepared, and originally recommended as a collector for froth flotation harvesting of Chlorella vulgaris from culture medium. The performance of BCBD was compared with the results acquired using its conventional monomeric surfactant cetyl trimethyl ammonium bromide (CTAB). The bench-scale flotation results showed that BCBD had excellent collecting power for Chlorella vulgaris. Achieving the obviously superior flotation harvesting performance (flotation recovery increased by 21.4% and enrichment ratio increased by 22.9), the dosage of Gemini type BCBD collector is five times less than that of monomeric CTAB collector.

Flotation of sylvite from potash ore by using the Gemini surfactant as a novel flotation collector

Potash fertilizer ensures the necessary agricultural yields to feed an increasing world population. Over 80% of the world’s potash fertilizer is produced by the selective froth flotation of KCl (sylvite) from NaCl (halite). However, all the surfactants used in the potash froth flotation process are traditional monomeric surfactants contain a single similar hydrophobic group in the molecule, which leads to a low production efficiency. In this work, a novel Gemini surfactant, N,N'-bis (octadecyldimethyl)-1,4-butane diammonium dibromide (BOBD) was prepared, and originally recommended as a collector for froth flotation separation of sylvite from halite for potash ore. The performance of BOBD was compared with the results acquired using its traditional monomeric surfactant octadecylamine hydrochloride (OAH). The bench-scale flotation results showed that BOBD had excellent collecting power for sylvite and significant selectivity against halite at natural pH. Moreover, BOBD presented stronger desalination efficiency than OAH. The results gained with the Gemini collector were better in terms of KCl recovery and NaCl content than those gained with four times higher dosages of the conventional monomeric surfactant.

Morpholine-Based Gemini Surfactant: Synthesis and Its Application for Reverse Froth Flotation of Carnallite Ore in Potassium Fertilizer Production.

Potassium fertilizer plays a critical role in increasing the food production. Carnallite is concentrated by reverse froth flotation and used as a raw material to produce potassium fertilizer (KCl) in agriculture. However, all the surfactants used in the carnallite reverse flotation process are conventional monomeric surfactants contain a single similar hydrophobic group in the molecule, which results in a low production efficiency. In this work, a new morpholine-based Gemini surfactant, 1,4-bis (morpholinododecylammonio) butane dibromide (BMBD), was prepared and originally recommended as a collector for reverse froth flotation separation of halite (NaCl) from carnallite ore. The flotation results indicated BMBD had higher flotation recovery and stronger affinity of halite against carnallite compared with conventional monomeric surfactant N-(n-Dodecyl) morpholine (DDM). Fourier transform infrared spectra suggested that BMBD molecules were adsorbed on halite surface rather than the carnallite surface. Additionally, BMBD molecules can strongly reduce the surface tension of NaCl saturated solution. Considering the BMBD's unique properties, such as double reactive centers to mineral surfaces, double hydrophobic groups, and stronger surface tension reducing ability, made it be a superior collector for reverse flotation desalination from carnallite ores than DDM.

Synthesis, surface/interfacial properties, and biological activity of amide-based Gemini cationic surfactants with hydroxyl in the spacer group

Three amide-based Gemini cationic surfactants, 1, 3-2 (alkyl amide propyl dimethyl ammonium chloride) isopropyl alcohol (abbreviated to ADQ-n, where n represents the carbon number in the raw fatty acid of 8, 12 and 16) were synthesized by a facile synthetic route. The effect of hydrophobic chain length on surface/interfacial activities, electrolytes tolerance, wettability, foaming properties were investigated. The effect of electrolytes (NaCl and CaCl2) on the interfacial tension at the oil/water interface were discussed, and the biological activity was also tested. The results showed that ADQ-n have the higher surface activities than conventional monomeric surfactant. The critical micelle concentration (cmc) decreases with the increase of hydrophobic chain length, however, the surface tension at the cmc (γcmc) shows the opposite trend. There are few differences for maximum surface excess concentration (Гmax) and minimum area per molecule (Amin). ADQ-12 has the lowest interfacial tension value (4.1 × 10−3 mN/m) than other synthesized Gemini surfactants, this is attributed to the better compatibility between hydrophobic tail of ADQ-12 and kerosene. In addition, the addition of electrolytes is favorable to decrease interfacial tension at oil/water interface. ADQ-n demonstrated readily biodegradation (>97%) in comparison with conventional alkyl chain Gemini surfactants (<37%) after seven days and could be classified as biodegradable.

Research status and prospect of Gemini surfactant/polymer interactions

Gemini surfactants are constructed by two hydrophobic chains and two polar/ionic head groups covalently connected by a spacer group at the level of or in close vicinity to the head groups. Due to their special self-assembly ability, they are superior to the corresponding conventional monomeric surfactants in characteristic features, such as remarkably low critical micellar concentration (CMC), high surface activity, unusual rheological properties, multifarious aggregate structures, better wetting ability, and so on. Owing to these unique properties, gemini surfactants have shown great promise in various areas. Gemini surfactants have been attracting great attention in both the academic and industrial worlds. There is increasing pressure to reduce our dependency on resources and to reduce the load we place on the environment. Surfactant-based formulations for water purification pharmaceuticals, cosmetics, detergency and oil recovery normally contain water-soluble polymers. Surfactant/polymer mixtures can provide improved properties that neither the surfactant nor the polymer has when present alone. Greater efficiency in these mixture systems would both reduce consumption and decrease pollution. The unusual efficiency and versatility of gemini surfactants offer the possibility of developing much more efficient and functional surfactant/polymer systems. Therefore, the interactions between gemini surfactants and polymers (containing polyelectrolytes, nonionic polymers, and hydrophobically modified polymers) have attracted considerable attention. It is important to systematically characterize the interactions between gemini surfactants and polymers, which can offer effective guidance to design the surfactant/polymer mixtures with desired properties by using such highly efficient surfactants. Here, we summarize the systems investigated in our laboratory, combined with the studies from other researchers, to give a comprehensive review on research progress of gemini surfactant/polymer interactions. This review will include the following three parts, (1) interaction between the cationic gemini surfactants m - s - m and polyelectrolytes, nonionic polymer, and hydrophobic modified polymer; (2) interaction between the special gemini surfactant and different polymers; (3) conclusion and prospect. Although the research of gemini surfactants/polymer interactions have made some progress, the more systematic studies still be needed due to the continuous innovation and development of gemini surfactant structure. In order to further to improve the efficiency of the gemini surfactant, a kind of novel oligomeric surfactants have been developed in the recent years. As compared with the gemini surfactants, the oligomeric surfactants have the more hydrophilic headgroups and hydrophobic alkyl chains, and the more complex molecular configuration. From the existing reports, it is found that the oligomeric surfactants have the very strong aggregation ability and very low critical micelle concentration. Some oligomeric surfactants can form the large aggregates by the strong intermolecular hydrophobic interaction at very low concentrations (only several micromoles), which will greatly improve the surfactant efficiency. At present, the studies on the oligomeric surfactant/polymer interaction are very scarce. For both gemini and oligomeric surfactant, the main reasons to limit their large-scale application are the difficult synthesis and high cost of these surfactants. In order to solve these problem, the constructed gemini and oligomeric surfactants by the non-covalent interactions have been developed in recent years. By mixing the conventional surfactants with special structure of organic acid or salt, we have successfully constructed many kinds of gemini and oligomeric surfactants, and these surfactants exhibited the similar aggregation behaviour just like the synthesized surfactants. The systematic studies on the interaction between the constructed gemini or oligomeric surfactants with the different polymer are also needed. With the deeply understanding to the gemini surfactant/polymer interaction, the researchers will gradually optimize the properties and functions of surfactant/polymer complex system, and strive for the realization of the large-scale application of gemini surfactants in the industrial fields.

A novel cationic Gemini surfactant with amide group: synthesis and micellization behavior in aqueous solutions

Novel cationic Gemini surfactant with amide group, N 1,N 10-bis(3-dodecanamidopropyl)-N 1,N 1,N 10,N 10-tetramethyldecan-1,10-diammonium bromide (abbreviated as 2C12enAm) has been synthesized by two-step reactions, purified and characterized in our laboratory. The critical micelle concentration (CMC) values of this Gemini surfactant were determined using electrical conductivity and surface tension measurements in the range of temperatures from 298.15 to 328.15 K. It was observed that the CMC value of Gemini surfactant has a much lower value compared with monomeric ones and shows a slight increase with an increase in the temperature. The interactions between Gemini and conventional monomeric surfactant hexadecyltrimethylammonium bromide (CTAB) have been studied using the conductivity at a certain micellar concentration and temperature range. Rubingh’s theory is used to evaluate the micellar interaction parameters (β) for the mixed systems. It has been observed that mixed micelle formation in all the binary mixtures exhibited negative synergism (antagonism) or ideal behavior due to positive β values. Thermodynamics parameters were also obtained from the temperature dependence of the CMC values. From the surface tension measurements, CMC, maximum surface excess concentration at the solution/air interface (Γmax), minimum area per surfactant molecule (A min), the surface pressure at CMC (ΠCMC), the surfactant concentration required to reduce the surface tension of solvent by 20 mN m−1 (pC20), and thermodynamic parameters have been evaluated at same temperatures.

On the Spacer Group Effect on Critical Micelle Concentration of Cationic Gemini Surfactants Using Molecular Connectivity Indices.

The important factor which differentiates gemini surfactants from conventional monomeric surfactants is the spacer group. The molecular connectivity method was used to study the effect of the spacer group on critical micelle concentration of cationic gemini surfactants. Two models were derived employing only Kier and Hall molecular connectivity indices. The relationships were developed for a set of 17 gemini surfactants with various spacer groups only. These models can be used to design the structure of the spacer group and in consequence novel cationic gemini surfactants more active in micelle formation.

Effect of (chloride salt) electrolytes on the mixed micellization of (equimolar) a cationic gemini (dimeric) surfactant and a cationic conventional (monomeric) surfactant

ABSTRACTHerein we report the effect of (chloride salt) electrolytes on the mixed micellization of (equimolar) a cationic gemini (dimeric) surfactant, hexanediyl-1,6-bis(dimethylcetylammonium bromide) (16-6-16), and a cationic conventional (monomeric) surfactant, cetyltrimethylammonium bromide (CTAB) in aqueous solutions. In absence and presence of (chloride salt) MCl (where M˭Li, Na, and K) electrolytes, the critical micelle concentration (CMC) of mixed (16-6-16 + CTAB) surfactants was measured by surface tension measurements. With increasing the concentration of electrolyte, the CMCs were increasing. The surface properties and the thermodynamic parameters of the mixed micellar systems were also evaluated. From these evaluated thermodynamic parameters, it was found that in presence of electrolyte the stability of the mixed micellar system is more.

Micellization and mixed micellization of cationic gemini (dimeric) surfactants and cationic conventional (monomeric) surfactants: Conductometric, dye solubilization, and surface tension studies

ABSTRACTIn the present study, we have investigated the self-association, mixed micellization, and thermodynamic studies of a cationic gemini (dimeric) surfactant, hexanediyl-1,6-bis(dimethylcetylammonium bromide (16-6-16)) and a cationic conventional (monomeric) surfactant, cetyltrimethylammonium bromide (CTAB). The critical micelle concentration (CMC) of pure (16-6-16 and CTAB) and mixed (16-6-16+CTAB) surfactants was measured by electrical conductivity, dye solubilization, and surface tension measurements. The surface properties (viz., C20 (the surfactant concentration required to reduce the surface tension by 20 mN/m), ΠCMC (the surface pressure at the CMC), Γmax (maximum surface excess concentration at the air/water interface), Amin (the minimum area per surfactant molecule at the air/water interface), etc.) of micellar (16-6-16 or CTAB) and mixed micellar (16-6-16+CTAB) surfactant systems were evaluated. The thermodynamic parameters of the micellar (16-6-16 and CTAB) and mixed micellar (16-6-16+CTAB) surfactant systems were also evaluated.

Role of cationic gemini surfactants (m-s-m type) on the oxidation of d-glucose by permanganate

Cationic gemini (m-s-m type; m=16, s=4,5,6) surfactants were used to determine the micelles assisted kinetics parameters, mechanism of permanganate-D-glucose redox system in an aqueous solution by means of UV–visible spectroscopy at 40°C. Effects of different [gemini surfactant], [permanganate], [D-glucose] and temperature on the reaction rate were investigated. Various activation parameters such as activation energy (Ea), enthalpy of activation (ΔH#), free energy of activation (ΔG#), and entropy of activation (ΔS#) have been evaluated. Menger-Portony pseudo-phase model modified by Bunton was used to analyze the role of gemini surfactant on the rate constant. Spacer chain length of surfactants has significant impact on the oxidation -reduction kinetics. A suitable mechanism reliable with the experimental results has been proposed and discussed. The cationic gemini surfactant micellar media are relatively more efficient than conventional monomeric surfactant i.e. cetyltrimethylammonium bromide (CTAB).

Interaction between copper(II) complex of glycylphenylalanine and ninhydrin in aqueous–micellar solutions of gemini surfactants

In the present study, we have reported the interaction between copper(II) complex of glycylphenylalanine, [Cu(II)-Gly-Phe]+, and ninhydrin in aqueous–micellar solutions of gemini surfactants (16-s-16, s=4, 5, 6). The reaction showed first- and fractional-order dependencies, respectively, on [complex] and [ninhydrin]. The surfactants used in this reaction are a dicationic gemini and its catalytic behavior was also seen on the reaction rate. It is found that dicationic gemini surfactants are more effective than the respective monomeric surfactant (CTAB) with the same number of carbon atoms in the hydrophobic chain per hydrophilic head group. Moreover, while the typical rate constant (kΨ) increases and leveling-off regions, same as conventional monomeric surfactant CTAB (cetyltrimethylammonium bromide), are observed with geminis, the latter produced a third region of increasing kΨ at higher concentrations. The observed micellar catalysis is interpreted by the means of pseudo-phase model of the micelles (proposed by Menger and Portnoy and developed by Bunton). The values of thermodynamic parameters and binding constants were also evaluated by using the observed kinetic data.

Investigations on reverse cationic flotation of iron ore by using a Gemini surfactant: Ethane-1,2-bis(dimethyl-dodecyl-ammonium bromide)

In this paper, a Gemini surfactant, ethane-1,2-bis(dimethyl-dodecyl-ammonium bromide) (EBAB), was introduced as a collector for reverse cationic flotation separation of quartz from magnetite, and its adsorption mechanisms on the two minerals and air/water interface were also investigated by FTIR spectra, zeta potential, density functional theory (DFT) calculation and surface tension. The flotation results showed that EBAB presented stronger collecting power than the conventional monomeric surfactant dodecylammonium chloride (DAC) and superior selectivity for quartz against magnetite. The results of FTIR spectra and zeta potential measurements demonstrated that the interaction of EBAB with quartz and magnetite was mainly through electrostatic attraction, which was further confirmed by DFT calculation. EBAB was preferred to adsorb on the negatively charged surface of quartz, increasing its zeta potentials and improving its hydrophobicity. Adsorption of EBAB at the quartz/water interface could be divided into four stages as the concentration of EBAB was increased in solution. At low concentrations, adsorption was controlled primarily by electrostatic interactions, but when the zeta potential of quartz was reversed from negative to positive, hydrophobic chain interactions controlled the adsorption process. EBAB’s unique properties, such as high positive grouping Mulliken charge of –CH2N+(CH3)2(CH2)2(CH3)2N+CH2–, and strong “surface activity” at the air–water interface, made it be a superior cationic collector for reverse flotation desilication from iron ores.

Interaction between cationic gemini surfactant and related single-chain surfactant in aqueous solutions

In this paper, the gemini surfactants of type alkanediyl-α-ω-bis (alkyldimethylammonium) dibromide with different spacers containing s carbon atoms, referred to as “16-s-16” [C16H33(CH2)2N+(CH2)SN+(CH2)2C16H33·2Br−], (s=2, 6, 10 and Ar (8)) have been synthesized, purified and characterized in our laboratory. The interactions between geminis and their conventional monomeric surfactant hexadecyltrimethylammonium bromide (CTAB) have been studied using the conductivity and steady-state fluorescence quenching techniques at a certain micellar concentration range and certain temperature. Using the conductance data, the values of critical micelle concentrations (CMC) of the binary gemini–conventional mixtures having different compositions have been obtained. The micellar interaction parameters, (β), were determined from the critical micelle concentration values using the approach of Rubingh's regular solution theory. Mixed systems were exhibited negative synergism due to positive β values. The β values were found as close to zero. This indicates that the mixed micelle formation is ideal for all studied mixtures. The micelle aggregation numbers (Nagg), evaluated using steady-state fluorescence quenching at a total concentration of 2mM for CTAB/16-s-16 (s=2, 6, 10 and Ar (8)) systems. It was observed that contribution of conventional surfactants was always more than that of the geminis. Using the ratio of peak intensities, the micro-polarity, dielectric constant and binding constant (Ksv) of mixed systems were determined.