Cationic Gemini Surfactants Research Articles

Adsorption of tungstate using cationic gemini surfactant-modified montmorillonite: Influence of alkyl chain length

Influence of alkyl chain length on the adsorption characteristics of organic pollutants by conventional cationic surfactant-modified montmorillonite (Mt) has been well explored. However, applying different cationic gemini surfactants to modify Mt for the adsorption of pollutant that possesses different species in aqueous solution to insightfully understand the structure-property relationship is rarely reported. In this study, three gemini surfactants with different alkyl chain lengths (number of carbon atoms, m = 12, 14, and 18) are selected to regulate the distribution and configuration in the composites. Tungstate, an emerging pollutant, is chosen as a probe, and its different species are modulated by changing the adsorption temperature and pH. The molar contents of the three surfactants are negligibly affected by the alkyl chain length, while the distributions of surfactants in the interlayer space and on the external surface are different. Lengthening the alkyl chain increases the packing density, lowering the accessibility of adsorption sites and decreasing the uptake of tungstates. At lower temperatures and pH values, polytungstates are the predominant species in the solution and are more favorably immobilized by the modified Mt. Ion exchange with Br − ions and desorption-adsorption are jointly responsible for the adsorption of tungstates, and both of these processes are configuration-dependent. The modified Mt by the gemini surfactants with longer alkyl chains demonstrates a lower ion exchange percentage and a more remarkable uptake of tungstates on the external surface. The adsorption of tungstates is accompanied by the rearrangement of gemini surfactants. Thus, elucidating the self-accommodation mechanism of cationic gemini surfactants during tungstates adsorption on modified Mt will provide a significant reference for the design of cationic surfactant- modified clay minerals used for pollutant immobilization. • Gemini surfactant-modified montmorillonite (Mt) was used to remove tungstate. • Gemini surfactant configuration is modulated via changing alkyl chain length. • Lower temperature and pH are beneficial for tungstate uptake on modified Mt. • Polytungstates are more favorably immobilized by the modified Mt. • Tungstate uptake was accompanied with the surfactant self-accommodation.

Effect of spacer hydroxyl number on the performance of Gemini cationic viscoelastic surfactant for fracturing fluids

The performance of Gemini cationic viscoelastic surfactant (VES) is affected by the spacer group, which is also the focus for developing the molecular structure design of high -performance clean fracturing fluid. In this study, we synthesized Gemini cationic VESs (VES-O, VES-DO, VES-TO) by introducing different number of hydroxyl groups in the spacer. The effect of the number of hydroxyl groups in the spacer on the performance of Gemini cationic VES was investigated using surface tension measurement, apparent viscosity and viscoelasticity tests in the presence of KCl. Further, the performance of clean fracturing fluids containing VES-O, VES-DO, and VES-TO were evaluated. We discovered that increasing numbers of hydroxyl groups in the spacer improves surfactant performance in fracturing fluid and high-elasticity fracturing fluids with low viscosity. This gives us ideas for future designs of high-performance clean fracturing fluids.

A novel cationic surfactant synthesized from carbon quantum dots and the versatility

An approach of manufacturing a novel cationic surfactant derived from carbon quantum dots with versatility of fluorescence, surface activity and antibacterial performance was described in detail in this work. Firstly, hydrothermal treatment was carried out on mixture of citric acid, N,N-dimethylethylenediamine and hydrogen peroxide for obtaining the carbon quantum dots (represented with OX-CQDs). Successively, quaternization of OX-CQDs with 1-chlorododecane was executed in ethanol medium for preparing the novel cationic surfactant (represented with OX-CQDs-C12H25). The measurement showed that the fluorescent quantum yield of OX-CQDs-C12H25 approached 23.13%. Surface tension of the dilute solution reached a minimum of 30.0 mN m−1, which was comparable to some cationic Gemini surfactants. Additionally, it performed synergistic surface effect when OX-CQDs-C12H25 was mixed with sodium dodecylbenzene sulfonate. Also, OX-CQDs-C12H25 still performed well in inhibiting growth of Escherichia coli when the solution was diluted to 0.21 mg mL−1. Such performances of OX-CQDs-C12H25 were superior to that of the cationic surfactant obtained by similar way without hydrogen peroxide in surface activity, fluorescent quantum yield and antibiosis for Escherichia coli.

Hydrogen production from the steam reforming of bioethanol over novel supported Ca/Ni-hierarchical Beta zeolite catalysts

This paper studies the H2 production via the steam reforming of a bioresource-derived ethanol mixture over supported Ca-modified Ni-hierarchical Beta zeolite catalysts. The results showed that the hierarchical Beta zeolite with rich pore structure could be synthesized in one step by using the new quaternary ammonium gemini cationic surfactant. The zeolite had bigger BET area and pore volume than the traditional Beta zeolite. The support plays a key role for the improve of catalytic behavior. The internal structure of the catalyst can be changed by introducing calcium and nickel ions into the synthesized zeolite at the same time through ion exchange. The interaction between active metal and the support would increase, so the dispersion of the active metal can be improved. The intermediate CO2 was efficiently absorbed by Ca in situ, which is an exothermic reaction and also help to provide the heat for the reactor. The adsorption of СО2 in situ transmitting the reversible reforming and water gas shift reactions to the products outside their conventional thermodynamic restrictions, which enhanced H2 production and permits high conversion to be attained. By using the method of gradient distribution of active metal in the support, the repeated catalytic effect similar to that of a hierarchical reactor was constructed, which showed excellent catalytic effect in low and medium high temperature bioethanol reforming to hydrogen. The experimental results show that when the reaction temperature is 350 °C, the 10Ni-MBeta(DI) catalyst maintains stable catalytic efficiency for continuous hydrogen production of 50 h via ESR, high hydrogen production and good stability.

Synthesis of Gemini Cationic Surfactant for proficient extraction of uranium (VI) from sulfuric acid solution

Synthesis of Gemini Cationic Surfactant for proficient extraction of uranium (VI) from sulfuric acid solution

Novel cationic Gemini ester surfactant as an efficient and eco-friendly corrosion inhibitor for carbon steel in HCl solution

The corrosion inhibition behaviors of a cationic gemini surfactant with hydrolyzable ester groups in its C18 tails from natural palmitic acid were tested for carbon steel in 1.0 M HCl solution. The synergistic effect of the eco-friendly gemini ester surfactant with salt additives was explored. The corrosion inhibition efficiency was determined by weight loss measurement, potentiodynamic polarization and electrochemical impedance spectroscopy. The gemini ester surfactant exhibited high inhibition efficiency (94.5% at the concentration of 6.9 × 10-5 M). Synergistic inhibition effect was observed between the surfactant and the salt additives, with the maximum corrosion inhibition efficiency as high as ~98.4%. The surfactant acted as a mixed type inhibitor with predominant inhibition of cathodic reactions. The adsorption behavior obeyed the Langmuir isotherm model with chemisorption between the inhibitor and carbon steel. Quantum chemical modeling indicates the formation of coordinate bonds between the surfactant and the metal surface. Surface analysis using SEM/EDS, AFM and water contact angle measurements confirmed the high effectiveness of the gemini ester surfactant on the protection of carbon steel in HCl solution, and the synergistic effect on corrosion inhibition between the surfactant and sodium salicylate was verified intuitively.

Effect of the Substituent Position on the Phase Behavior and Photoresponsive Dynamic Behavior of Mixed Systems of a Gemini Surfactant and trans-Methoxy Sodium Cinnamates.

Mixed systems of the Gemini cationic surfactant trimethylene-1,3-bis (dodecyldimethylammonium bromide) (12-3-12·2Br-) and the photosensitive additives trans-methoxy sodium cinnamates with different substituent positions (trans-ortho-methoxy cinnamate, trans-OMCA; trans-meta-methoxy cinnamate, trans-MMCA; and trans-para-methoxy cinnamate, trans-PMCA) were selected for investigating the effects of the substituting position of methoxy on the system phase diagram and UV light-responsive behavior of the wormlike micelles. The differences in phase behaviors of the selected systems were analyzed by calculating the potential distribution, molecular volume, and free energy of solvation of cinnamates and the binding energies between photosensitive additives and the surfactant. The photoresponsive behaviors of wormlike micelle solutions formed in the selected systems were studied by the rheological method and UV-vis and H nuclear magnetic resonance (1H NMR) spectroscopy; the kinetics of photoisomerization of trans-OMCA, trans-MMCA, and trans-PMCA were studied by first-order derivative spectrophotometry. The results reveal that the methoxy substituent position has a great influence on the phase behavior and photosensitivity of the studied systems. In addition, the photoisomerization of the studied cinnamates follows the first-order opposite reaction laws; the different reaction rates play the decisive role in the photosensitivity of the wormlike micelles. This paper would afford a deeper understanding of the UV light-responsive mechanism at the molecular level and provide essential guidance in preparing smart materials with adjustable light sensitivity.

Drug induced catanionic vesicles assisted fabrication of hollow silica nano-spheres as the new age chemo-drug carrier

Surfactant vesicles have elicited the attention because of their non-toxic nature, ease of preparation, low cost programmable drug delivery vehicle and soft templates for the organized nano-assemblies. To unleash their potential as the new age drug carrier, herein we have designed catanionic vesicles formed through synergistic interactions between the hydrotropic drug diclofenac sodium (DS) and cationic gemini surfactants (GS) with varying alkyl chain lengths i.e. hexamethylene 1,6-bis (tetradecyl dimethyl ammonium bromide); and hexamethylene 1,6-bis (hexadecyl dimethyl ammonium bromide). The prepared catanionic vesicles were then used as the soft templates to synthesize hollow silica nano spheres with 62 nm size and 0.86 cm3/g pore volume to accommodate the anti-cancer drug imatinib mesylate. Results of encapsulation and release demonstrate that the studied system could potentially serve as a stable nano-delivery system for delivering the hydrophobic drugs in the future.

Novel macrocyclic cationic surfactants: Synthesis, experimental and theoretical studies of their corrosion inhibition activity for carbon steel and their antimicrobial activities

Morpholinomethylnaphthalene-1-ol (MMN-OH) and 2, 6-Bismorpholinomethyl naphthalene-1, 5-diol (BMND-OH) were synthesized via Mannich reaction. The novel monomeric cationic surfactant (DHNMMB) and gemini cationic surfactant (DHNBMBDMB) were obtained based on the previous Mannich compounds through quaternization reaction. The resulting structures confirmed by IR, 1HNMR, and mass spectroscopies. Gravimetric and electrochemical techniques were utilized to assess the inhibitory activity of the synthesized surfactants on CS deterioration in 5% HCl. We note that DHNBMBDMB is better than DHNMMB. This is due to the chemical structure and surface properties. The maximum inhibition performance of DHNBMBDMB and DHNMMB at 2.5 × 10−3 M is 96.14 and 94.65%, respectively. Tafel curves indicated that the DHNMMB and DHNBMBDMB were hybrid-type inhibitors. Adsorption of DHNMMB and DHNBMBDMB onto CS surface obey Langmuir model. Both DFT and MC simulation studies ofDHNMMB and DHNBMBDMB compounds are discussed thoroughly and agree with the laboratory experimental corrosion tests. SEM & AFM photos show a good CS surface in the presence of DHNMMB andDHNBMBDMB versus the absence of them. The antimicrobial activities of all the synthesized Mannich bases and their surfactants were tested. The surfactants had a talented effect against Candida albicans.

Spontaneous imbibition characteristics of carbon nanofluids in carbonate reservoirs

Altering the wettability of the rock–oil–brine system plays a substantial role in the oil recovery process from carbonate reservoirs. Hence, there arises a need for understanding the wetting and wettability alteration of this system. In this study, we ran a suite of spontaneous imbibition tests and investigated the efficiency of Carbon nanodots (CND) and an in-house cationic Gemini surfactant (GS8) on the wettability alteration of and recovery from oil-wet carbonate rock samples. The study considered the effects of additives concentrations, sample aging, initial water saturation, and rock permeability. Both CND and GS8 proved efficient at concentrations below 200 ppm. At 200 ppm, separately CND in seawater and GS8 in seawater demonstrated each about 22%–25% incremental oil recovery over neat seawater. Low field nuclear magnetic resonance (NMR) measurements supported this observation. NMR T2 distribution and NMR T2D fluid typing measurements helped evaluate the recovery in terms of the pore size distribution and the oil and brine water saturation at different imbibition stages. CND exhibited a strong positive effect on the wettability of all tested samples, and accordingly, on the imbibition characteristics and oil recovery. It altered the wettability from strongly oil-wet to water-wet with equal efficiency in all pore systems making it a strong candidate for enhanced oil recovery (EOR). GS8, on the other hand, was most efficient in the macropores. Unlike CND, the efficiency of GS8 decreased in the mesopores and more so in the micropores. Rock–oil–brine surface contact angle and oil–brine interfacial tension measurements supported the imbibition test results and helped interpret the recovery mechanism. Overall, CND proved effective for EOR in the harsh carbonate reservoir environment and demonstrated itself as a viable and economical substitute to the more costly and complex oilfield chemicals for recovery operations.

Synergistic interactions in the mixed micelles of anionic amino acid surfactant with cationic gemini surfactant

The synergistic interactions in the mixed micelles of anionic amino acid surfactant SMS with cationic gemini surfactant 12-3-12 and single-chain surfactant DTAB have been investigated. The fluorescence probe measurements reveal that the critical micelle concentration (CMC) and micellar micropolarity (I1/I3Micelles) of SMS/12-3-12 and SMS/DTAB mixed micelles are always lied below the individual surfactants and reach the minimum values at equimolar compositions, which indicates the synergistic electrostatic attraction and hydrophobic interaction in the mixed micelles. Comparing with SMS/DTAB mixed micelles, the double charged headgroups and two alkyl chains lead 12-3-12 to have stronger synergistic interactions with SMS to form SMS/12-3-12 mixed micelles, which can be confirmed by the experimental values of CMC, I1/I3Micelles, zeta potential, and the various micellar parameters calculated from Clint’s and Rubingh’s models. When sodium bromide (NaBr) is added, SMS/DTAB mixed micelles have more markedly decreased values of CMC and I1/I3Micelles, but there are slight changes in SMS/12-3-12 mixed micelles. This result is ascribed to more tightly packed structure of SMS/12-3-12 mixed micelles than SMS/DTAB mixed micelles. The salt effect is also explained by the fact that the chaotropic ion Br- and the kosmotropic ion Na+ have different counterion specificities on two mixed micelles.

Gemini surfactant-assisted fabrication of graphene oxide/polyaniline towards high-performance waterborne anti-corrosive coating

Graphene oxide/polyaniline (GO/PANI) has been demonstrated to be an effective anti-corrosive nanofiller in polymer matrix, however, its hydrophobility restricts its application in waterborne polymer coatings. Here, cetyltrimethylammonium bromide (CTAB) and cationic gemini surfactant (GS) with the same constitutional unit as CTAB were adopted to fabricate CTAB modified GO/PANI (CGO/PANI) and GS modified GO/PANI (GGO/PANI). The incorporation of GS not only increased the intercalation degree of GO nanosheets but also functionalized as dopant to improve the electrochemical properties of PANI. The dispersibility and compatibility of GGO/PANI in waterborne alkyd resin (WAR) were also higher than that of CGO/PANI, resulting in the formation of more uniform nanocomposite coating. Compared with pure WAR, the coating resistance of GGO/PANI/WAR increased by 4 orders of magnitude, the corrosion density decreased by 3 orders of magnitude and the corrosion potential shifted from −0.72 V to −0.28 V. GGO/PANI/WAR also displayed enhanced long-term anti-corrosive properties in comparison with CGO/PANI/WAR.

Performance Test and Application Research of New Gemini Wetting Dust Suppressant

In order to solve the problem of low efficiency of dust-catching by water mist to the hard-to-wetting and respirable dust, a new wetting type dust suppressant of Gemini was proposed based on the analysis of the wetting effect of water mist. Based on the evaluation indexes of surface tension, contact Angle, wetting and settling rate of dust spray, the performance of polyquaternary ammonium salt AG-101, dodecanol polyoxyethylene etheryl dimethyl ammonium chloride, octyl alcohol polyoxyethylene etheryl dimethyl decyl ammonium chloride and macromolecular cationic PCD Gemini surfactants were optimized, and had carried on the dust-suppression performance in a certain open-pit iron mine field experiment research. The results show that the comprehensive dust suppression performance of mass concentration of 2.0% of quaternary ammonium salt polymer AG-101 is the best, indoor experimental tests showed the dust rate is 4.2 times the speed of water, the field test showed that the initial wetting speed is 4.4 times the speed of water, and the action time of dust and water mist suppression is shortened obviously. The field application proves that the total dust removal efficiency is 82.3% (water is 56.6%), which is 45.4% higher than that of water. The dust removal efficiency of respirable dust is 92.1%, which is 16.5% higher than that of water. The research results provide a new dust suppressing agent for optimization of mine spray dust removal.

Synthesis, Characterization, Antibacterial Activity, and Interfacial and Micellar Features of Novel Cationic Gemini Surfactants with Different Spacers

AbstractIn the present study, four novel imidazolium‐based cationic gemini surfactants (IBCGS) have been synthesized, having same hydrocarbon chain lengths and different spacers. The impacts of type and nature of spacer on Krafft temperatures (TK) have been examined. Micellization behaviors of IBCGS have been investigated at different temperatures above TK by both surface tension and specific conductivity measurements. Surface activity properties of aqueous systems have been calculated using the results of the measurement data. Critical micelle concentration (CMC), surface pressure at CMC (ПCMC), minimum area of head group (Amin), degree of counterion binding (β), degree of counterion dissociation (α), and maximum surface excess (Γmax) of IBCGS have been calculated with data of surface tension and specific conductivity. IBCGS have low CMC values than other imidazole categories of gemini and monomeric cationic surfactants. Micelle aggregation number (Nagg) values have been determined with the steady‐state fluorescence quenching method. The values of Nagg have been found in the range of 19–28. Additionally, the antibacterial activities of IBCGS on gram‐positive and gram‐negative bacteria have been investigated. IBCGS studied in this article have showed perfect antibacterial activity particularly against gram‐positive bacteria. The data obtained in this study may be benefical for the surfactant applications in different areas.

Inhibitory influence of cationic Gemini surfactant on the dissolution rate of N80 carbon steel in 15% HCl solution

Strong acids are commonly used in petroleum wells to remove scale layers from the surface of N80 C-steel pipe. The corrosive effects of these acids, on the other hand, pose a significant risk to C-steel pipes. For the first time, we discovered the anti-corrosion properties of cationic Gemini surfactant, 1,2-bis(dodecyldimethylammonio) ethane dibromide (DMAEB), for N80 C-steel pipe in acid washing solution (15.0% HCl). The DMAEB, in particular, can reduce the corrosion rate of N80 C-steel by approximately 97%. DMAEB molecules work as a mixed-type corrosion inhibitor, according to electrochemical results. The DMAEB demonstrated a high inhibition effect at high temperatures, as well as high activation energy against the corrosion process. DMAEB's significant performance is primarily due to physical adsorption on the N80 C-steel surface, as confirmed by adsorption isotherms, SEM, EDX, FT-IR, and theoretical studies. Our findings shed new light on the use of Gemini surfactants as corrosion inhibitors in petroleum wells.

Fabrication and characterization of encapsulated Gemini cationic surfactant as anticorrosion material for carbon steel protection in down-hole pipelines

Nowadays, modern society is confronting a remarkable challenge to oil and gas production because of the associated corrosion problems that consider a standout amongst the most troublesome issues in the oil and gas industry. The process of transfer and controlling the release of corrosion inhibitors to the bottom of deep oil wells is a major problem. To address this pressing issue, an encapsulated tetramethyl-N,N-bis(3-palmitamido-propyl)propane-1,3-diaminium (TPPD) as an eco-friendly Gemini cationic surfactant has been engineered as anticorrosion material to protect carbon steel constructing the down-hole pipelines. The TPPD capsules were manufactured and encapsulated by gel capsules of calcium alginate. The release of the corrosion inhibitor TPPD was investigated in 0.5 M H 2 SO 4 /formation water solution over time. The FT-IR, and Thermal gravimetric (TGA) analysis have been conducted for investigating the successful engineering of the alginate TPPD capsule. The gradually release of TPPD from the engineered alginate capsules to the corrosive solution were studied using UV–visible spectroscopy. The efficacy of carbon steel protection by the encapsulated gemini surfactant was examined by Tafel polarization, electrochemical, and impedance spectroscopy. The scanning electron microscopy (SEM) clarified the good protection of steel surface by the TPPD inhibitor. The released TPPD inhibitor behaves as a mixed type inhibitor with physisorption/chemisorption affinity based Langmuir adsorption isotherm. • A Gemini cationic surfactant corrosion inhibitor TPPD was successfully engineered into alginate capsule. • The release of TPPD inhibitor from the alginate capsule was monitored by UV–Vis spectra. • The engineered TPPD capsule provided a continuous release of TPPD inhibitor over time. • The electrochemical polarization clarified the mixed type inhibitor performance of the TPPD inhibitor. • Langmuir adsorption isotherm with physisorption/chemisorption tendency were predicted.

Determination of the Aggregation Number of Pyrene-Labeled Gemini Surfactant Micelles by Pyrene Fluorescence Quenching Measurements.

A cationic gemini surfactant referred to as Py-3-12 and composed of two alkylated diammonium bromide head groups, a propyl spacer, and dodecyl and 1-pyrenehexyl hydrophobic tails was synthesized. Its critical micellar concentration (CMC) was determined to equal 0.15 (±0.02) mM by surface tension and time-resolved fluorescence measurements. The state of the pyrene molecules, whether they were incorporated inside the Py-3-12 micelles or unassociated in the aqueous solution, was determined by applying the global model-free analysis (MFA) to the fluorescence decays acquired with Py-3-12 aqueous solutions. The unassociated Py-3-12 surfactants emitted as pyrene monomers and showed a long fluorescence lifetime. The excited pyrenyl groups located inside Py-3-12 micelles formed an excimer by a rapid encounter with a ground-state pyrene with an average rate constant equal to 0.69 (±0.06) ns-1. After having the photophysical properties of Py-3-12 in aqueous solution characterized, the number (Nagg) of surfactants per micelle was determined by conducting quenching experiments with dinitrotoluene (DNT). Although DNT is fairly hydrophobic, it was found to partition itself between the Py-3-12 micelles and the aqueous phase. Fluorescence quenching experiments performed on the pyrene monomer and excimer generated by the Py-3-12 aqueous solutions yielded the concentration ([Q]b) of DNT bound to the Py-3-12 micelles and the average number ⟨n⟩d of DNT quenching an excimer by diffusive encounters. A combination of steady-state and time-resolved fluorescence quenching experiments on the excimer yielded the number (⟨n⟩s) of DNT molecules that were bound to the micelles and quenched the excimer in a static manner. A plot of the sum ⟨n⟩d + ⟨n⟩s as a function of [Q]b yielded an Nagg value of 14.0 (±0.2) Py-3-12 units per micelle. This study represents the first example in the literature where Nagg is determined for a micelle, where each surfactant molecule is labeled with pyrene.

Ester-Gemini and Monomeric Cationic Surfactants; Synthesis, Characterization, Surface Parameters and Biological Activity

Gemini cationic surfactant is a promising generation of surfactants characterized by their unique surface properties and biological activities. Herein, a series of three Gemini cationic surfactants containing ester bond with different alkyl chain length and their corresponding monomeric structures have been synthesized. The monomeric surfactant were synthesized via simple esterification of different fatty acids (stearic, myrisitic, lauric acid) with 2-dimethyl amino ethanol, followed by quaternization with 1-bromohexane; while, and 1,6-dibromohexane was used to prepare the corresponding Gemini cationic surfactants. The structures of the synthesized compounds were elucidated using 1H-NMR, FTIR spectroscopy. The biological activities and surface properties have been assayed and it was found that the prepared Gemini surfactants have higher antimicrobial efficiencies than the corresponding monomeric structure.

Plasma-aided green and controllable synthesis of silver nanoparticles and their compounding with gemini surfactant

The compounding of surfactants with specific nanomaterials may result in a system of multi-functionalities. In this work, silver nanoparticles (AgNPs) were prepared by a microplasma-aided approach, where traditional chemical reductants were not required. The influence of plasma conditions and parameters on the product (e.g. composition, structure) was studied via characterization techniques like UV–Vis, SEM, TEM, EDX, XRD, SAED, OES and HRTEM. Results showed that crystalline AgNPs of high purity can be directly obtained in one step, without any chemical reducing agents. Meanwhile, a gemini cationic surfactant (Tetramethylene-α,ω-bis(lauryloxyethyl dimethyl lammonium bromide)) of superior surface activity and well antibacterial property was synthesized, and then compounded with the plasma-generated AgNPs to form a nano-surfactant system. By evaluating their antibacterial activity against E. coli and S. aureus, the synergistic effects of the compounding system were studied. It was demonstrated that AgNPs were well-dispersed in the presence of the gemini cationic surfactant, and the nano-surfactant compounding system has improved antibacterial activity as well as good stability.

Micellization and clouding singularity amid the mixture of EO-PO-based star-block copolymer and cationic surfactants in aqueous solution

We herein report the micellization study on mixtures of poly(ethylene oxide)-poly(propylene oxide) (PEO-PPO) star-block copolymer, Tetronics®1304 (T1304) with several cationic conventional and Gemini surfactants (GS) using plethora of physicochemical techniques viz. cloud point (CP), tensiometry, fluorescence, dynamic light scattering (DLS) and small angle neutron scattering (SANS). The results indicate resilient interactions of T1304 with GS in comparison to the conventional analogues with similar alkyl chain length. The presence of cationic surfactants, at lower temperature, induces micellization. Hence, a significant drop can be noted in the critical micellization temperature (CMT) of T1304 as observed from the spectral study. However, in the post-micellar regime, the presence of cationic surfactants enhance the surface charge on the copolymeric micelle which leads to the micellar breakdown resulting into the formation of mixed micelles. Addition of salt, on the contrary, compensated the effect of surfactants and counteracted the hydrophilicity generated in the presence of surfactants.