Cationic Gemini Surfactants Research Articles

Temperature controlled comparative physico-chemical studies of DTAB and 12-2-12 Gemini surfactants in aqueous solutions of fructose, maltose and raffinose

The Micellar behaviour of synthesised cationic Gemini surfactant ethanediyl-1,2-bis (dimethyldodecylammonium bromide) and its single-chain counter-part i.e., Dodecyltrimethylammonium bromide (DTAB) in absence and presence of carbohydrates (fructose, maltose and raffinose) has been investigated. The conventional technique viz. surface tension measurements over a wide range of temperature, (293.15–313.15K with an interval of 5K) and spectroscopic method i.e. fluorescence probe at room temperature have been employed to determine critical micelle concentrations (CMC's) of both the surfactants. The decrease in CMC have been found for both the studied surfactants; however the effect being more prominent in case of Gemini surfactant (GS). From surface tension data, various interfacial parameters have been evaluated that reflects the presence of stronger electrostatic attractions between carbohydrates and the micelle of surfactants. The CMC values calculated using both the studies have been found to be in good agreement and corroborate each other's observations.

Design, synthesis, anticorrosion efficiency, and applications of novel Gemini surfactants for preparation of small-sized hollow spheres mesoporous silica nanoparticles

The unique properties of Gemini surfactants and their variety of applications encouraged many researchers to synthesize more of these compounds. Herein, we constructed new cationic Gemini surfactants by using aromatic spacers with different chain lengths. The critical micelle concentration value for each surfactant was determined using the electrical conductivity measurements. The variety of aggregation behaviors of Gemini surfactants was studied by using atomic force microscopy, which encouraged us to use these surfactants in the preparation of mesoporous silica NPs. Our results indicated that we have succeeded in finding a new soft-template for preparing uniform small size hollow spheres mesoporous silica NPs of a diameter depending on the used surfactant. Moreover, we investigated the effect of pH value on the morphology of the prepared silica, which indicated that using of acidic media resulted in the formation of hollow micro-particles instead of hollow NPs. Furthermore, the anti-corrosion efficiency of these surfactants in comparing with cetyltrimethylammonium bromide (CTAB) as a positive control was investigated by monitoring the corrosion rate of iron sheets in 0.5 M of hydrochloric acid based on weight loss method. Our results indicated that all the prepared Gemini surfactants possessed higher anti-corrosion efficiency at very low concentrations than CTAB surfactant.

Drug-Induced Micelle-to-Vesicle Transition of a Cationic Gemini Surfactant: Potential Applications in Drug Delivery.

An impetus for the sustained interest in the formation of vesicles is their potential application as efficient drug-delivery systems. A simple approach for ionic surfactants is to add a vesicle-inducing drug of opposite charge. In ionic gemini surfactants (GSs) two molecules are covalently linked by a spacer. Regarding drug delivery, GSs are more attractive candidates than their single-chain counterparts because of their high surface activity and the effect on the physicochemical properties of their solutions caused by changing the length of the spacer and inclusion of heteroatoms therein. Herein, the effect of the (anionic) anti-inflammatory drug diclofenac sodium (DS) on the morphology of aqueous micellar aggregates of gemini surfactant hexamethylene-1,6-bis (dodecyldimethylammonium) dibromide (12-6-12) at 25 °C is reported. Several independent techniques are used to demonstrate drug-induced micelle-to-vesicle transition. These include UV/Vis spectrophotometry, dynamic light scattering, TEM, and small-angle neutron scattering. The micelles are transformed into vesicles with increasing [DS]/[12-6-12] molar ratio; precipitation of the catanionic (DS-GS) complex then occurred, followed by partial resuspension of the weakly anionic precipitate. The stability of some of the prepared vesicles at human body temperature shows their potential use in drug delivery.

Self assembly in an aqueous gemini surfactant containing sugar based (isosorbide) spacer

Effect of various stimuli (concentration, pH, temperature and salt) have been investigated, in aqueous isosorbide (sugar based) spacer based cationic gemini surfactant with hexadecyl chain (16-Isb-16), using spectroscopic and physico-chemical techniques (dynamic light scattering, DLS; nuclear magnetic resonance, NMR; transmission electron microscopy, TEM; polarizing optical microscopy; POM; zeta (ζ)-potential; count rate; pH and conductometry). An interesting phenomenon of micelle to vesicle transition (MVT) has been observed upon dilution. pH sensitive systems, including micelles and vesicles, are found in the solution without changing the pH externally. For external pH change (in the acidic range), DLS data revealed that vesicles are present near the neutral pH. The morphological transitions were confirmed by TEM and POM. ζ data show the conversion of positively charged aggregates to neutral ones. MVT has also been checked by increasing the temperature or adding a salt (NaCl, NaBr, NaNO3 or sodium salicylate; NaSal). Heating induces a transition from micelles to vesicles near ∼40–45 °C while salt addition causes a reverse effect (vesicle to micelle). The transition has been found to be dependent on concentration/nature of salt. The study provides a simple and effective way of tuning the micellar morphology.

Novel Gemini cationic surfactants as anti-corrosion for X-65 steel dissolution in oilfield produced water under sweet conditions: Combined experimental and computational investigations

Two new sequences of Gemini di-quaternary ammonium salts were synthesized characterized by FTIR and 1HNMR spectroscopic techniques and evaluated as corrosion inhibitor for X-65 steel dissolution in deep oil wells formation water saturated with CO2. The anti-corrosion performance of these compounds was studied by different electrochemical techniques i.e. (potentiodynamic polarization and AC impedance methods), Surface morphology (SEM and EDX) analysis and quantum chemical calculations. Results showed that the synthesized compounds were of mixed-type inhibitors and the inhibition capability was influenced by the inhibitor dose and the spacer substitution in their structure as indicated by Tafel plots. Surface active parameters were determined from the surface tension profile. The synthesized compounds adsorbed via Langmuir adsorption model with physiochemical adsorption as inferred from the standard free energy (ΔG°ads) values. Surface morphology (SEM and EDX) data for inhibitor (II) shows the development of adsorbed film on steel specimen. Finally, the experimental results were supported by the quantum chemical calculations using DFT theory.

Gemini Surfactant-Modified Activated Carbon for Remediation of Hexavalent Chromium from Water

Gemini surfactants, with double hydrophilic and hydrophobic groups, offer potentially orders of magnitude greater surface activity compared to similar single unit molecules. A cationic Gemini surfactant (Propyl didodecyldimethylammonium Bromide, PDDDAB) and a conventional cationic surfactant (Dodecyltrimethylammonium Bromide, DTAB) were used to pre-treat and generate activated carbon. The removal efficiency of the surfactant-modified activated carbon through adsorption of chromium(VI) was investigated under controlled laboratory conditions. Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) were used to investigate the surface changes of surfactant-modified activated carbon. The effect of important parameters such as adsorbent dosage, pH, ionic strength and contact time were also investigated. The chromium(VI) was adsorbed more significantly on the Gemini surfactant-modified activated carbon than on the conventional surfactant-modified activated carbon. The correlation coefficients show the data best fit the Freundlich model, which confirms the monolayer adsorption of chromium(VI) onto Gemini surfactant-modified activated carbon. From this assessment, the surfactant-modified (especially Gemini surfactant-modified) activated carbon in this study showed promise for practical applications to treat water pollution.

Adsorption Properties of Gemini and Monomeric Cationic Surfactants on Sandstone and Silica Nanoparticles

The surface modification of pore throat by adsorption of surfactants is thought to have a positive effect on water flooding in low and ultralow permeability reservoirs. In this paper, Gemini cationic surfactants, containing 12 and 16 carbon alkyl chains(ethanediyl-1,2-bis(dimethyl dodecyl ammonium bromide) and ethanediyl-1,2-bis(dimethyl cetyl ammonium bromide), referred to as GC12 and GC16) and hexadecyl trimethyl ammonium bromide (CTAB) were used as modifying agents to investigate the effects of the surfactant concentration, adsorption time and temperature on static adsorption onto the surface of sandstone and silica nano particles (NPS). The results show that the equilibrium adsorption amount of GC16 on sandstone and NPS is higher than that of GC12 on sandstone and NPS with the same initial concentration of 0.225 mmol/L in solution at 45°C. It is found that the adsorption amounts of GC12 and GC16 decrease as the raise of temperature. The adsorption rate of surfactant on sandstone surface is slower than that of NPS. The equilibrium adsorption time of these surfactants on sandstone is 20 h, while the time of NPS is only 2 h. At 55°C, the static saturation absorption amount of GC12 is 210.56 μmol/g on NPS and 117.67 μmol/g on sandstone, while the amounts of CTAB on sandstone and NPS under static conditions are 1.18 times and 1.46 times of GC12, respectively. Considering the number of tail chain in a molecule of surfactant, the packing densities of Gemini surfactants on solid surface are higher than that of the single-tail surfactant (CTAB). Therefore, the adsorption rate and amount of surfactant are affected by the specific surface of solid particles, charged density, tail chain number and length of the cationic group.

Experimental Investigation of Newly Synthesized Gemini Cationic Surfactants as Corrosion Inhibitors of Mild Steel in 1.0 M HCl

Three Gemini cationic surfactants named N1,N1,N3,N3-tetramethyl-N1,N3-bis(3-octanamidopropyl) propane-1,3-diaminium bromide (C8-S3-C8), N1,N1,N3,N3-tetramethyl-N1,N3-bis(3-dodecanamidopropyl) propane-1,3-diaminium bromide (C12-S3-C12) and N1,N1,N3,N3-tetramethyl-N1,N3-bis(3-hexadecanamidopropyl) propane-1,3-diaminium bromide (C16-S3-C16) were evaluated as corrosion inhibitors for mild steel in 1.0 M HCl. The corrosion rate of mild steel in 1.0 M HCl at three different temperatures 25, 45 and 60oC was investigated gravimetrically. The corrosion rate of mild steel was confirmed electrically at 25oC. The corrosion inhibition efficiency directly proportionally with the hydrophobic chain length of inhibitors. The inhibition efficiency exhibit a positive trend with raising the solution temperatures. The potentiostatic polarization study revealed that the tested gemini cationic surfactants act as mixed type inhibitors with predominant control of cathodic reaction. The Villamil isotherm provide the best describing of the adsorption process on the selected steel in 1.0 M HCl. The adsorption of the tested inhibitors on the steel surface is a mixture of chemical and physical adsorption.

Synthesis of a Novel Gemini Cationic Surfactant and Its Inhibition Behaviour and Mechanism Study on 2024 Al-Cu-Mg Alloy in Acid Solution

Isopropylamine was taken as a raw material to synthesize a new multi-alkyl multiple quaternary-ammonium salts gemini surfactant bis[2-hydroxy-3-(dodecyldimethylammonio)propyl]-isopropylamine dichloride. The structure of the synthetic product was characterized by1H NMR and FTIR. The surface activity was investigated; the inhibition efficiencies and inhibition mechanism of the synthetic product were studied by weight loss method, electrochemical method, microscopic morphology observation, and adsorption model calculation. The results indicate thatcmcof synthetic product was 9.204 ×10-4 mol/L; when the concentrations were lower thancmc, the inhibition efficiencies rose substantially, which was up to 89.3% with the concentration of 9.204 × 10-4 mol/L; when they were higher thancmc, inhibition efficiencies were basically unchanged; polarization tests showed that the synthesis product could restrain both anodic and cathodic reactions; when the concentrations were lower thancmc, the adsorption of the synthetic product conformed to the Langmuir model, which formed monolayer on the 2024 Al-Cu-Mg alloy surface; when they were higher thancmc, it formed bilayer, so the adsorption of the synthetic product did not conform to the Langmuir model anymore.

Ionic liquid mediated micelle to vesicle transition of a cationic gemini surfactant: a spectroscopic investigation.

In this contribution, we have examined a composition dependent self aggregated structural modification of a catanionic mixture of the surface active ionic liquid (IL) 1-butyl-3-methylimidazolium octyl sulphate and a cationic gemini surfactant (14-5-14) in aqueous medium. We have observed that the hydrodynamic diameter of the aggregates increases with increasing IL concentration and microscopic evidence (HRTEM, FESEM, and LCSM) shows the formation of vesicle like aggregates (Dh ≈ 200 nm) at XIL = 0.5. The steady state fluorescence anisotropy of the membrane binding probe DPH shows a micelle to vesicle transition at this composition. The viscosity of the solution shows a peak at XIL = 0.3, indicating the formation of a worm like micelle as an intermediate of the micelle to vesicle transition. The rotational dynamics shows a stiffer surfactant packing in the vesicles compared to the micelles, whereas, the solvation dynamics measurements indicate a higher abundance of bound type water in the vascular medium compared to that for the micelle. The formed vesicles also show stability towards temperature and biomolecules, which can be used for respective applications.

The Effect of a Cationic Gemini Surfactant, Ethonium, on the Physicochemical Properties of Quercetin in Solutions and on the Surface of Highly Dispersed Silica

The formation of supramolecular complexes with ethonium, a cationic gemini surfactant having a broad-spectrum antimicrobial activity, is shown to significantly alter the physicochemical properties (spectral, protolytic, and adsorption properties and solubility) of a natural f lavonol, quercetin. The constant of binding between quercetin and ethonium is calculated. Apparent dissociation constants pK a1 a of quercetin in solutions of this cationic surfactant are for the first time determined within a broad concentration range. A shift in the pH dependence of quercetin adsorption by 0.5 units to the alkaline region upon the transition from a premicellar ethonium solution to a micellar one correlates with an increase in pK a1 a under these conditions. The value of quercetin adsorption from aqueous ethonium solutions depends on the concentration of the cationic surfactant, pH of a solution, and the pK a1 a value of the f lavonol bound into the supramolecular complex.

Transfection by cationic gemini lipids and surfactants.

Diseases that are linked to defective genes or mutations can in principle be cured by gene therapy, in which damaged or absent genes are either repaired or replaced by new DNA in the nucleus of the cell. Related to this, disorders associated with elevated protein expression levels can be treated by RNA interference via the delivery of siRNA to the cytoplasm of cells. Polynucleotides can be brought into cells by viruses, but this is not without risk for the patient. Alternatively, DNA and RNA can be delivered by transfection, i.e. by non-viral vector systems such as cationic surfactants, which are also referred to as cationic lipids. In this review, recent progress on cationic lipids as transfection vectors will be discussed, with special emphasis on geminis, surfactants with 2 head groups and 2 tails connected by a spacer.

The Influence of Electrolytes on the Mixed Micellization of Equimolar (Monomeric and Dimeric) Surfactants

The influence of halide ions of (sodium salt) electrolytes on the mixed micellization of a cationic gemini (dimeric) surfactant, hexanediyl-1,6-bis(dimethylcetylammonium) bromide (16-6-16) and a cationic conventional (monomeric) surfactant, cetyltrimethylammonium bromide (CTAB) have been investigated. The critical micelle concentration (CMC) of the mixed (16-6-16+CTAB) surfactants was measured by the surface tension measurements. The surface properties: viz., the surfactant concentration required to reduce the surface tension by 20 mN/m (C20), the surface pressure at the CMC (ΠCMC), the maximum surface excess concentration at the air/water interface (Γmax), the minimum area per surfactant molecule at the air/water interface (Amin), etc. of the mixed micellar surfactant systems were evaluated. In the absence and presence of electrolytes, the thermodynamic parameters of the mixed micellar surfactant systems were also evaluated.

Effects of additives on the viscoelastic responses of cationic gemini surfactant solutions.

Several additives, including inorganic (NaCl) and organic salts (derivatives of benzoate), were added into aqueous solutions of a gemini cationic surfactant, 2-hydroxypropyl-1,3-bis (myristyldimethylammonium chloride) (abbreviated as 14-3(OH)-14(2Cl)). The mixed systems were investigated using rheological measurement, cryo-TEM and 1H NMR analysis. The results showed that addition of salts induced rich aggregate morphologies in the 14-3(OH)-14(2Cl)/salt systems. The influence of an inorganic salt on the viscoelasticity of 14-3(OH)-14(2Cl) solutions is much weaker than that of organic salts. Furthermore, the ability of three organic salts in enhancing the viscoelasticity of 14-3(OH)-14(2Cl) solutions is in the order sodium m-hydroxybenzoate > sodium o-hydroxybenzoate > sodium p-hydroxybenzoate. The different roles of these organic salt isomers arise from the different types of hydrogen bonding formed between 14-3(OH)-14(2Cl) and the organic counter ions.

Aqueous solution behaviour and solubilisation properties of octadecyl cationic gemini surfactants and their comparison with their amide gemini analogues.

Gemini surfactants 18-s-18(Et), comprised of two ethylammonium headgroups and two alkyl tails with m = 18 carbon atoms with spacers of s = 4, 6, 8 and 10 linking the headgroups (alkanediyl-α,ω-bis(diethyloctadecylammonium bromides)), were obtained. Their aqueous solution behaviour, including adsorption at the interface and aggregation in solution, was followed by tensiometric, conductometric and spectroscopic methods. The critical micelle concentration (CMC) of the surfactants decreased with increasing spacer length. The size of 18-s-18(Et) aggregates formed at concentrations of 10 and 40 CMC measured by DLS varied with the elongation of the spacer. Visualisation of aggregated surfactant structures at 40 CMC by cryo-TEM evidenced the formation of different morphologies depending on spacer length. Gemini with s = 4 formed elongated, cylindrical micelles, while geminis of s = 6, 8 and 10 self-assembled into vesicles. The ability of the studied geminis to solubilise hydrophobic dye Sudan I in water was determined as a function of surfactant concentration, demonstrating their high efficiency. Results for 18-s-18(Et) geminis were compared with those previously obtained for their analogues containing an amide group placed between headgroups and tails. The significant impact of amide groups on the surface activity and aggregation properties of gemini surfactants was evidenced and is related to hydrogen-bond formation by amide-containing compounds.

Cationic Gemini Surfactant-Plasmid Deoxyribonucleic Acid Condensates as a Single Amphiphilic Entity.

A critical aggregate concentration for the surfactant-DNA "complex" or "condensate" consisting of the 16-3-16 gemini surfactant and circular plasmid DNA was determined using surface tensiometry, dynamic light scattering, and conductometry. This surfactant-DNA complex acts as an amphiphile itself, for example, decreasing the surface tension of water until a critical concentration is reached. The evidence presented here introduces a new way of considering these surfactant-DNA condensates, not simply as aggregates in solution but as surface-active agents in their own right. At concentrations below the critical aggregate concentration, there is some dissociation of surfactant molecules from the condensate, creating a more "loose" or "relaxed" complex; however, at and above the critical aggregate concentration, the surfactant-DNA system forms smaller and more uniformly distributed condensates once again. This behavior is analogous to demicellization/micellization that occurs in typical surfactant systems.

The study of imidazoles Gemini surfactants as retarders for the dyeing of cationic dyes on polyacrylonitrile fabrics

Alkyl imidazole cationic Gemini surfactants (AICGS) with various alkyl chain lengths were used as retarders for dyeing methylene blue (MB) on polyacrylonitrile (PAN) fabrics, with benzyldimethyldodecylammonium chloride (1227) surfactant as a comparison. The exhaustion (E%) of MB on PAN fabrics was investigated at varying surfactant concentrations and dyeing temperatures. Furthermore, kinetic studies on various retarders and 10‐4‐10 AICGS concentrations were carried out. It was found that the retarding dyeing effect of AICGS is stronger when compared with the 1227 surfactant. Moreover, as surfactant concentration increased or the dyeing temperature decreased, E% was reduced drastically. For kinetic studies, the dyeing rate constant increased with an increase in dyeing temperature and a decrease in 10‐4‐10 AICGS concentration, while half‐dyeing time was reversibly decreased.

Enhanced oil recovery from high‐salinity reservoirs by cationic gemini surfactants

ABSTRACTIn order to enhance oil recovery from high‐salinity reservoirs, a series of cationic gemini surfactants with different hydrophobic tails were synthesized. The surfactants were characterized by elemental analysis, infrared spectroscopy, mass spectrometry, and 1H‐NMR. According to the requirements of surfactants used in enhanced oil recovery technology, physicochemical properties including surface tension, critical micelle concentration (CMC), contact angle, oil/water interfacial tension, and compatibility with formation water were fully studied. All cationic gemini surfactants have significant impact on the wettability of the oil‐wet surface, and the contact angle decreased remarkably from 98° to 33° after adding the gemini surfactant BA‐14. Under the condition of solution salinity of 65,430 mg/L, the cationic gemini surfactant BA‐14 reduces the interfacial tension to 10−3 mN/m. Other related tests, including salt tolerance, adsorption, and flooding experiments, have been done. The concentration of 0.1% BA‐14 remains transparent with 120 g/L salinity at 50 °C. The adsorption capacity of BA‐14 is 6.3–11.5 mg/g. The gemini surfactant BA‐14 can improve the oil displacement efficiency by 11.09%. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46086.

The kinetics and effect of a new gemini surfactant on the efficiency of micellar catalysis for the hydrolysis reaction of 4-nitrophenyl acetate

A new cationic gemini surfactant containing amide bond (C12-4-C12) was synthesized through a simple two-step procedure, and its chemical structure was confirmed by IR, 1H NMR spectroscopy and element analysis. The physical and chemical properties of the gemini surfactant in aqueous solution were investigated by surface tension and conductivity. The results show that the gemini surfactant possess good surface properties. The effect on the hydrolysis reaction rate constant (K) of 4-nitrophenyl acetate (PNPA) and the kinetics of the hydrolysis reaction with the gemini surfactant (C12-4-C12) was studied by means of spectrophotometry. The experimental results showed that the efficiency of micellar catalysis by gemini surfactant C12-4-C12 was significantly higher than that of the traditional single-chained surfactant CTAB. The possible liquid-liquid biphasic micellar catalyzed model was presented, which might be beneficial for the further study of the mechanism of liquid-liquid biphasic reaction.

Electrochemical measurements and semi-empirical calculations for understanding adsorption of novel cationic Gemini surfactant on carbon steel in H2SO4 solution

A novel imidazolium-based cationic Gemini surfactant (GS) was synthesized, characterized and evaluated as a corrosion inhibitor for carbon steel in 0.5 M H2SO4 using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The results revealed that this Gemini surfactant can act as an effective mixed-type inhibitor (ηp ∼ 90%) for carbon steel via adsorption of its molecules on the metal surface according to Langmuir adsorption isotherm. The synthesized GS showed a good synergistic inhibitory action with Ce3+cations and Iˉ anions in 0.5 M H2SO4 medium (ηp ∼ 93% and 95%, respectively). Thermodynamic activation parameters for the dissolution process of carbon steel in blank and inhibited sulfuric acid solution were calculated and discussed. A suitable equivalent circuit was used to analyze the experimental EIS data and modeling the inhibition process. Quantum chemical calculations have revealed that the tested Gemini surfactant can interact with Fe surface through electron transfer from the metal atom to surfactant molecule.