Carboxylate Gemini Surfactant Research Articles

Synthesis, interfacial activity and rheological properties of low interfacial tension viscoelastic Gemini surfactants

In order to develop a special surfactant that is suitable for improving oil recovery in low permeability reservoirs, and simultaneously meet the requirements of effectively improving sweep efficiency, displacement efficiency and good injectability, a series of new Gemini surfactants (GAC-3m, m = 14, 16, 18) were synthesized and characterized by FTIR and 1 HNMR. The surface activity, interfacial activity, thickening properties and viscoelasticity of GAC-3m solution were systematically studied. The mechanism of viscosity and elasticity enhancement were also discussed. The results showed that with increasing the carbon number of hydrophobic chain, the surface activity and interface activity of GAC-3m surfactant increased first and then decreased, the viscosity and elasticity gradually increased. The micelle microstructures changed from sheet to network-like, and the structural morphology was gradually complete and compact, which made the viscosity and elasticity of the GAC-3m surfactant solution increase. GAC-3m exhibit fascinating surface activity, interfacial activity and low values of CMC (<4.5 × 10 −4 mol/L), which is conducive to the formation of micelle structure at low concentration. The 0.5% GAC-316 solution can substantially reduce the oil-water interfacial tension to ultralow values (10 −3 mN/m), and also possess attractive viscosity (18.58 mPa s) and viscoelastic properties (tanδ = 0.5 < 1). In accordance with the experimental studies, the novel surfactants (GAC-3m) are a kind of low interfacial tension viscoelastic Gemini surfactant, promising in enhancing the recovery of low permeability reservoirs. The insights gained from this study contribute to enriching the theoretical research of the viscoelastic Gemini surfactant and promote the applications of low interfacial tension viscoelastic Gemini surfactant in the recovery of heterogeneous low permeability reservoirs fields. • A series of new carboxylate Gemini surfactants GAC-3m were synthesized and characterized by FTIR and 1 HNMR. • The interfacial activity, thickening property, viscoelasticity and thickening mechanism of GAC-3m solution were studied. • GAC-3m exhibit fascinating surface activity and low CMC, which is conducive to forming micelle structure at low concentration. • GAC-316 can reduce the interfacial tension to ultralow values, and also possesses attractive viscosity and viscoelasticity. • GAC-3m possess favorable shear-thinning behavior which is desirable for improving mobility control during EOR processes.

Study on the structure–activity relationship between the molecular structure of anionic Gemini surfactants and the rheological properties of their micelle solutions

In this study, the viscosity and viscoelasticity of Gemini surfactant solutions with different molecular structures were measured, and the micelle structure formed by self-assembly in the solution was observed and measured using FESEM and DLS. The effect of the molecular structure of anionic Gemini surfactants on the rheological properties of the solution was studied systematically. The experimental results showed that the carboxylate Gemini surfactants with long hydrophobic carbon chains and a moderate spacer group have better rheological properties in aqueous solution. The carboxylate Gemini surfactant solution aggregated to form more densely, larger-sized micelle structures than the sulfonate Gemini surfactant, so its viscosity and viscoelasticity are greater. When the carbon number of the spacer group was the same (s = 2), as the carbon number of the hydrophobic chain increased (m = 14,16,18), the hydrodynamic diameter increased, the size of the micelle structures formed by self-assembly in the solution increased, the micelles aggregated more tightly, and the solution viscosity and viscoelasticity increased. When the carbon number of the hydrophobic chain was the same (m = 18), as the carbon number of the spacer group increased (s = 2,3,4), the hydrodynamic diameter first increased and then decreased, the micelle structures exhibited the phenomenon of aggregation first and then disintegration, and the solution viscosity and viscoelasticity also increased first and then later decreased. These phenomena indicated that the change of Gemini surfactant molecular structure would lead to the change of its micelle microstructure and eventually lead to the change of solution rheological properties.

Synthesis and Properties of Carboxylate Gemini Surfactants

Synthesis and Properties of Carboxylate Gemini Surfactants

Synthesis, Surface Activity, Thermodynamic Parameters, and Performance Evaluation of Branched Carboxylate Gemini Surfactants

AbstractThree novel carboxylate gemini surfactants (3CntaDA, n = 8, 10, and 12) were synthesized by two simple steps, and their structures were characterized using FT‐IR and 1H NMR. The surface activities of these surfactants were obtained from surface tension measurements at different temperatures, and the surface parameters containing the critical micelle concentration (CMC), surface tension (γ), minimum surface area per molecule ( Amin), and maximum surface excess concentration ( Γmax) were obtained from surface tension measurements. The experimental results show that 3CntaDA surfactants have higher surface activities compared with the corresponding conventional surfactants. The thermodynamic parameters of the micellization process were investigated, and the calculated results show that it was an exothermic and spontaneous process. The emulsification and foam performance of these surfactants were also evaluated at different concentrations at 298.15 K.

Controllable fabrication of stimuli-responsive fluorescent silica nanoparticles using a tetraphenylethene-functionalized carboxylate gemini surfactant

A fluorophore-free green synthetic strategy was presented for the preparation of stimuli-responsive FSNs, which could be further tuned using N16-TPE-N16.

Equilibrium and Dynamic Surface Properties of Cationic/Anionic Surfactant Mixtures Based on Carboxylate Gemini Surfactant

AbstractThe equilibrium and dynamic surface properties of cationic/anionic surfactant mixtures of carboxylate gemini surfactant (CGS12) and quaternary ammonium salts with different alkyl chain lengths were investigated, and the synergistic properties and solubilization capacity toward phenanthrene of these mixtures were evaluated. Results show that all cationic/anionic surfactant mixtures exhibit negative interaction parameters, indicating the strong synergistic effects in the reduction of surface tension and the formation of micelles. When the mixing ratio is 1:1, the surface tension reaches the minimum value. Moreover, as the alkyl chain length increases, the interaction parameters become more negative. In addition, the thermodynamic parameters suggest that the formation of mixed micelles is exothermic with a positive change in entropy. The tendency of dynamic surface tension curves of these mixtures is similar to that of pure CGS12. At the same concentration, these mixtures exhibit a higher adsorption rate than pure surfactants, and a lower adsorption potential barrier than cationic surfactants. However, for the CGS12/stearyltrimethylammonium bromide mixture, the drop rate constant of surface tension is lower than that of either component. Compared with the pure surfactant solutions, the cationic/anionic surfactant mixtures exhibit higher solubilization capacity toward phenanthrene. As the length of the alkyl chain increases, the solubilization capacity of the mixed cationic/anionic surfactant increases.

Correction to "Rational Design and Synthesis of Carboxylate Gemini Surfactants with an Excellent Aggregate Behavior for Nano-La2O3 Morphology-Controllable Preparation".

A series of carboxylate gemini surfactants (CGS, Cn-Φ-Cn, n = 12, 14, 16, 18) with diphenyl ketone as a spacer group were prepared using a simple and feasible synthetic method. These CGS exhibited an excellent surface activity with extremely low critical micelle concentration (CMC) value (approximately 10–5 mol/L), good performance in reducing surface tension (nearly 30 mN/m), and the ability of molecular self-assembly into different aggregate morphologies via adjusting the concentrations, which is attributed to the introduction of diphenyl ketone and carboxylic acid ammonium salt in the molecular structure. Moreover, the surface activity and self-assembly ability of CGS were further optimized by tuning the length of the tail chain. These excellent properties imply that CGS can be a soft template to prepare nanomaterials, especially in morphology-controllable synthesis. By adjusting the concentration of one of CGS (C12-Φ-C12), nano-La2O3 particles with diverse morphologies were obtained, including spheric...

Preparation of Gemini Surfactant/Conjugated Polymer Aggregates for Enhanced Fluorescence and Bioimaging Application.

Conjugated polymers have great potential applications in bioimaging. However, the aggregation of conjugated polymers driven by electrostatic and hydrophobic interactions in aqueous media results in the reduction of photoluminescence quantum efficiency. In present work we synthesized a carboxylate gemini surfactant [sodium 2,6-didodecyl-4-hydroxy-2,6-diaza-1,7-heptanedicarboxylate (SDHC)] to adjust the aggregation behaviors and fluorescence properties of conjugated polymers [anionic poly(2-methoxy-5-propyloxy sulfonate phenylene vinylene) (MPS-PPV) and cationic poly(3-alkoxy-4-methylthiophene) (PMNT)]. This gemini surfactant shows very low critical micellar concentration (CMC) in aqueous solution and forms vesicles above CMC. In neutral and acidic conditions, MPS-PPV combines with the SDHC vesicles mainly via hydrophobic interactions and forms the aggregates in which the photoluminescence quantum efficiency of MPS-PPV is highly enhanced from 0.1% to 27%. As to PMNT, the molecules are located in the bilayer of SDHC vesicles through both electrostatic and hydrophobic interactions, and this structure prevents the production and release of reactive oxygen species. Moreover, SDHC is nontoxic and can effectively decrease the dark- and photocytotoxicity of MPS-PPV and PMNT, laying a good foundation for their bioimaging application. The living cell imaging indicates that the surfactant/conjugated polymer aggregates can stain the MCF-7 cells with main location in the lysosome. This work provides insight into how to improve the fluorescence properties and bioimaging applications of conjugated polymers by surfactants.

Rational Design and Synthesis of Carboxylate Gemini Surfactants with an Excellent Aggregate Behavior for Nano-La2O3 Morphology-Controllable Preparation.

A series of carboxylate gemini surfactants (CGS, Cn-Φ-Cn, n = 12, 14, 16, 18) with diphenyl ketone as a spacer group were prepared using a simple and feasible synthetic method. These CGS exhibited an excellent surface activity with extremely low critical micelle concentration (CMC) value (approximately 10-5 mol/L), good performance in reducing surface tension (nearly 30 mN/m), and the ability of molecular self-assembly into different aggregate morphologies via adjusting the concentrations, which is attributed to the introduction of diphenyl ketone and carboxylic acid ammonium salt in the molecular structure. Moreover, the surface activity and self-assembly ability of CGS were further optimized by tuning the length of the tail chain. These excellent properties imply that CGS can be a soft template to prepare nanomaterials, especially in morphology-controllable synthesis. By adjusting the concentration of one of CGS (C12-Φ-C12), nano-La2O3 particles with diverse morphologies were obtained, including spherical shape, bead-chain shape, rod shape, velvet-antler shape, cedar shape, and bowknot shape. This work offers a vital insight into the rational design of template agents for the development of morphology-controllable nanomaterials.

Cloud point phenomena in aqueous solutions of an anionic gemini surfactant with a dibenzene spacer in the presence of tetra-n-propyl-ammonium bromide

The cloud point behaviour of a carboxylate gemini surfactant,O,O′-bis(sodium 2-dodecylcarboxylate)-p-dibenzenediol was observed in the presence of tetra-propyl-ammonium bromide.

Alkyltrimethylammonium bromide-induced aggregate transition of carboxylate gemini surfactant with a p-dibenzenediol spacer from networks to thread-like micelles to vesicles

The gemini surfactants, O,O’-bis(sodium 2-dodecyl-carboxylate)-p-dibenzenediol and O,O’-bis(sodium 2-decylcarboxylate)-p-dibenzenediol (denoted as C12ϕ2C12 and C10ϕ2C10, respectively), were previously found to form network-like aggregates in very dilute solution. In the present work, the effect of alkyltrimethylammonium bromides, CnNBr, on the network-like aggregates formed by C12ϕ2C12 and C10ϕ2C10 was studied using dynamic light scattering, fluorescence probing, steady-state or frequency sweep rheology, and freeze-fractured TEM measurements. These network-like aggregates were easily transformed into core-shell micelles as CnNBr was added, including spherical micelles and even thread-like micelles, upon increased concentration of CnNBr. On further increasing CnNBr concentration, vesicles were formed. The phase diagrams of aggregate transition were plotted. All of these were attributed to the improvement of added CnNBr on the effective molecule geometry under the base of original columnar-like molecules of C12ϕ2C12/C10ϕ2C10.

Micellization of anionic gemini surfactants and their interaction with polyacrylamide

A series of anionic gemini surfactants have been synthesized. The surface properties and micellization process of as-prepared sulfonate gemini surfactants (SGS) and carboxylate gemini surfactant (CGS) have been studied by surface tension measurement and isothermal titration microcalorimetry. Meanwhile, the interaction of these five surfactants with polyacrylamide (PAM) was investigated using surface tension, steady-state fluorescence measurement, and isothermal titration microcalorimetry. The results show that the critical micelle concentrations (CMCs) of above-mentioned surfactants are more than 1 order of magnitude lower than those of corresponding single chain surfactants. Moreover, the enthalpy of micelle formation (ΔH mic) for the investigated gemini surfactants is negative. In the surfactant–PAM systems, the thermodynamic parameters of binding have also been determined. The conclusion may be drawn that the binding strength of SGS onto PAM is stronger than that of CGS, resulting from more compact structure of SGS aggregates. With increasing surfactant hydrophobicity, the values of ΔH agg become more exothermic and a ΔS agg decrease was observed. Therefore, the interaction between SGS and PAM is enthalpy-driven.

The strong influence of alkyl tail length on the aggregation and viscoelasticity of carboxylate gemini surfactants with a p-dibenzenediol spacer in aqueous solution

This paper reports a study on the aggregation and rheological behavior of the family of O, O’-bis(sodium 2-alkylcarboxylate)-p-dibenzenediol (referred to as Cmϕ2Cm, m = 10, 12, 14, respectively) in aqueous solution using dynamic light scattering, 1H NMR and rheology measurements. The results showed that all three surfactants formed large network-like aggregates at low concentrations. However, C10ϕ2C10 formed small compact micelles simultaneously but neither C12ϕ2C12 nor C14ϕ2C14 did. These network-like aggregates were transformed into the wormlike micelles with increasing the surfactant concentration. The length of alkyl tails was found to strongly affect the viscoelasticity of wormlike micellar solutions. From C10ϕ2C10, C12ϕ2C12 to C14ϕ2C14 in turn, the system developed rapidly from the viscous fluid to typically viscoelastic solution and then to a solid-like gel. The scaling exponents of the concentration dependence of both zero-shear viscosity (η 0) and plateau elastic modulus (G′∞) greatly exceeded the theoretic predictions, showing fast micellar growth and strong entanglements between the wormlike micelles. For C14ϕ2C14 that had the longest alkyl tails in this series, the wormlike micelles formed at 140 mmol L−1 were quite long and the micellar reptation dominated over the scission and recombination. This system yielded a viscosity as high as 2.20 × 104 Pa⋅s at 25 °C.

Synthesis and Surface Tension Study of the Spacer Chain Length Effect on the Adsorption and Micellization Properties of a New Kind of Carboxylate Gemini Surfactant

AbstractA series of carboxylate gemini surfactants, which contain two hydrocarbon chains linked by amide groups, two carboxylate groups, a flexible alkane spacer were synthesized by three‐step reactions and named alkylidene–bis‐(N,N′‐dodecyl‐carboxypropylamides) (2C12H25CnAm; n = 2, 3, 4, 6, 8 is the number of methylene groups of the spacer), their structures were confirmed by FTIR,1H NMR, and LC–MS/TOF, and their purity checked by HPLC. The micellar properties with increasing spacer chain length of these gemini surfactants were determined by surface tension methods. The critical micelle concentration (CMC) varies slightly with spacer chain length; surface tension at CMC(γCMC), the tendency of micellization versus adsorption, CMC/C20, the minimum area per surfactant molecule at the air/solution interface (ACMC), all decrease with increasing spacer chain length; surface reduction efficiency, pC20, the surface excess at the air/solution interface (ГCMC) increase with increasing spacer chain length. The results probably indicate that increasing spacer chain length of these carboxylate gemini surfactants will increase spacer incorporation into the double hydrophobic chain.

Construction of a highly viscoelastic anionic wormlike micellar solution by carboxylate gemini surfactant with a p-dibenzenediol spacer

The viscoelastic wormlike micellar solutions formed by the carboxylate gemini surfactant, O,O′-bis(sodium 2-dodecylcarboxylate)-p-dibenzenediol (referred to as C12ϕ2C12), have been investigated by steady-state and dynamic frequency-sweep rheological techniques. Another system using its homologue, O,O′-bis(sodium 2-dodecylcarboxylate)-p-benzenediol (C12ϕC12), was also examined for comparison. Both C12ϕ2C12 and C12ϕC12 formed wormlike micelles without any additives. The C* corresponding to the onset of the semi-dilute regime was 48 mmol L−1 for C12ϕ2C12 and 160 mmol L−1 for C12ϕC12, respectively, showing the considerably high ability and efficiency of C12ϕ2C12 in forming wormlike micelles. The wormlike micelles started to entangle with each other at 60 mmol L−1 for C12ϕ2C12 and 300 mmol L−1 for C12ϕC12. The average length of the C12ϕ2C12 wormlike micelles was estimated to be about 1.0–1.9 μm, significantly longer than the C12ϕC12 ones. The solution viscosity of C12ϕ2C12 at 200 mmol L−1 reached 613 Pa s, much higher than 24.2 Pa s for C12ϕC12 at 500 mmol L−1. The mechanisms of forming wormlike micelles in both cases were revealed by dynamic light scattering measurements. Differently from the normal micellar growth that C12ϕC12 displayed, C12ϕ2C12 was found to form large network-like aggregates at very low concentrations. These aggregates could more conveniently transform into threadlike (wormlike) micelles by continuously increasing the concentration of C12ϕ2C12, from which a new approach was realised for highly viscoelastic anionic wormlike micellar solutions.

A Highly Viscoelastic Anionic Wormlike Micellar System

The rheological behavior of carboxylate gemini surfactant O,Oʹ-bis(sodium 2- tetradecylcarboxylate)-p-dibenzenediol (referred to as C14ϕ2C14) with a concentration of 140 mmol·L - 1 in aqueous solution in the presence of 100 mmol·L - 1

Unique Aggregation Behavior of a Carboxylate Gemini Surfactant with a Long Rigid Spacer in Aqueous Solution

A new gemini surfactant with a long and rigid spacer, O,O'-bis(sodium 2-dodecylcarboxylate)-p-dibenzenediol (referred to as C(12)φ(2)C(12)), has been synthesized. Its aggregation in aqueous solution has been studied using static and dynamic light scattering measurements. The homologue O,O'-bis(sodium 2-dodecylcarboxylate)-p-benzenediol (C(12)φC(12)) whose spacer only contains a single phenyl group was also examined for comparison. Dynamic light scattering (DLS) revealed the unexpected existence of large aggregates in the solution of C(12)φ(2)C(12). However, C(12)φC(12) showed rather normal aggregation behavior. Both the results of intrinsic viscosity and light scattering demonstrated a loose structure for the large aggregates of C(12)φ(2)C(12). This behavior was attributed to an extending configuration of C(12)φ(2)C(12) with the two alkyl tails stretching toward the solution due to the rigidity of the long spacer. The large network-like aggregate formation was an inevitable outcome of spontaneously reducing the energy of the system. Freeze-fracture transmission electron microscopy (FF-TEM) images and (1)H NMR measurements supported this speculation. Due to the columnar-like molecular geometry, the large network-like aggregates were directly transformed into rodlike micelles with increasing surfactant concentration. Depending on further micellar growth, the wormlike micelles were finally formed as confirmed by rheological measurements.

Synthesis and Properties of Novel Carboxylate Gemini Surfactant

The novel anionic gemini surfactant, isodium salt of N, N’, N”- trilauroyl-diethylenetriamine diacetate(TDAD), was synthesized with ethylenediamine, sodium chloroacetate and lauroyl chloride by displacement reaction and acylation reaction. The results show that TDAD has fairly low critical micelle concentration (cmc) and high surface activity. The adsorption isotherm of TDAD at the interface of oil sand/aqueous solution is taken on “S” model, and the adsorption loss of TDAD is much lower than that of the traditional monomer sodium laurate (SL).

Alkyl chain length-dependent viscoelastic properties in aqueous wormlike micellar solutions of anionic gemini surfactants with an azobenzene spacer

A homologue of carboxylate gemini surfactants with an azobenzene spacer and different lengths of the alkyl tails, referred to as Cm(azo)Cm, has been synthesized. All the surfactants formed wormlike micelles at relatively low concentrations without addition of salt. The reason was attributed to the long and rigid characteristic of the azobenzene spacer, which yielded the pseudo volume between the two tails and thus a columnar-like molecular geometry favorable for the formation of wormlike micelles. The results of rheology and FF-TEM measurements showed that the length of the alkyl tails strongly affected the viscoelastic properties of the wormlike micelle solution. With the increase of the alkyl tail length, the solutions evolved from a typically viscous fluid to a strong viscoelastic solution and then to a gel-like state. This was attributed to the different microstates as revealed by scaling law. These solutions behave as polyelectrolyte systems because of their additive-free nature.

Salt Effect on the Aggregation Behaviors of an Anionic Carboxylate Gemini and a Cationic Surfactant

The synthesis method and conditions for the carboxylate Gemini surfactant O,O′‐bis(sodium 2‐lauricate)‐p‐benzenediol (C11pPHCNa) were explored. Surface tension data of the single and mixed systems of catanionic (cationic with anionic) surfactants with different salt concentrations were used to determine the CMC values and to obtain the information of self‐assembly behaviors of the surfactants. Aggregates' morphologies were observed by transmission electron microscopy (TEM) and speculation was made according to the viscosity measurement results. The results show that large spherical aggregates formed in the mixed solution, which tend to transfer into branched and wormlike mixed micelles with the increases of the salt concentration. The viscosity of the mixed solution was found to increase gradually corresponding to the change of the catanionic surfactant mixtures' morphology.