Cationic Gemini Surfactants Research Articles

Micellar mediated preparation of cadmium sulfide (CdS) nanoparticles: Influence of cleavable spacer based cationic gemini surfactant

Cleavable spacer (s = diamido) based cationic gemini surfactant (with different alkyl tail lengths (m) abbreviated as g1; m = 12, g2; m = 14 or g3; m = 16), in aqueous micellar solution, was used to control the size and morphology of cadmium sulfide (CdS) nanoparticles (NPs), via modified chemical precipitation technique. The purity and stability of all CdS NPs were characterized by EDAX, FT-IR, TGA and zeta potential (ζ). By varying the geminis, significant size reduction (2–6 nm), enhanced capping capacity, and higher energy band gap (∼4.1 eV) have been found in CdS-g1 compared to other NPs, by using Dynamic Light Scattering (DLS), TEM, XRD and UV–visible spectroscopy. Photoluminescence (PL) spectra revealed an emission at 525 and 630 nm, showing the effect of geminis m concerning surface states of NP. Additionally, antioxidant and antimicrobial (on Gram-negative (E. coli and P. aeruginosa) and Gram-positive (S. aureus and B. subtilis) strains) activities of CdS NPs were examined by DPPH radical scavenging and agar plating-spot disc inoculation method, respectively. The results recommended a significant antioxidant activity in CdS-g1 with 45.6 %, while, selective antimicrobial activity was obtained on E. coli and S. aureus in all NP systems.

The Corrosion Inhibition Study of The Heat Exchanger Components in Chemical Cleaning Process Using the Synthesized new Cationic Gemini Surfactant

The Corrosion Inhibition Study of The Heat Exchanger Components in Chemical Cleaning Process Using the Synthesized new Cationic Gemini Surfactant

Surface engineered novel cationic surfactants with enhanced surface adsorption for environmental applications

Gemini Cationic Surfactants (GCS) have garnered significant attention due to their distinctive molecular structure, featuring two hydrophilic head groups associated with a hydrophobic spacer. This distinctive configuration enables diverse applications across various fields. Hence, the current study introduces a novel series of GCSs, ethanediyl-1,2-bis[di(2-hydroxypropyl) alkylammonium] dibromide (Cn-C2-Cn[IsoPr(OH)2; n = 9, 12 and 14) and comprehensively explore their properties, highlighting their promising antimicrobial activity. The synthesis of GCSs was validated using 1H NMR and IR spectroscopy. Dynamic Light Scattering was employed to determine the dimensions of Gemini surfactant aggregates in aqueous solutions. Surface tension analysis determined critical concentrations of micelle (CMC), minimum surface area (Amin) and concentration of surface excess (Γmax). Physicochemical properties were assessed through conductivity and surface tension analyses in aqueous solutions. The CMC, Amin and Γmax values decrease as alkyl chain length extends. Surface tension data revealed strong adsorption of GCSs at interfaces. π values (mN/m) ranged from 36.7 (C14C2C14[Iso-Pr(OH)]2) to 45.3 (C9C2C9[Iso-Pr(OH)]2). Conductivity and surface tension measurements further characterized Gemini surfactants in aqueous environments at 298 K. The size of the micelle aggregates varied between C9C2C9[Iso-Pr(OH)]2 (1.2885 nm) and C14C2C14[Iso-Pr(OH)]2 (1.9210 nm), highlighting the impact of chain length on micelle size. Hence, the study highlights significant effect of the chain lengths on Gemini cationic surfactants’ self-assembly in dilute aqueous environments. Antimicrobial tests demonstrated significant activity of Cn-C2-Cn[IsoPr(OH)]2 GCSs at varying concentrations. Antimicrobial tests showed the significant antimicrobial potential of these GCS compounds, suggesting their potential and promising applications in medical, hygiene, environmental sanitation and advanced materials sectors.

Role of gemini surfactants with biodegradable spacer as efficient capping agents of silver nanoparticles

Since the last decade, silver nanoparticles (AgNPs) continue to attract interest of both academia and industry due to their peculiar physical, chemical, and optical properties. In the field of pharmaceutical applications, they are efficient carriers in the processes of controlled drug release, improve the drug's bioavailability, act as efficient antimicrobial agents and provide other biological functions conveyed at the nanometric scale. The known issue hampering further development of applications of AgNPs is their instability in aqueous environment. The present study utilizes two series of cationic bisammonium gemini surfactants with two dodecyl chains and a biodegradable spacer containing two amide or ester groups for the stabilization of AgNPs. The presence of nanosilver in the dispersions was confirmed by UV–VIS plasmon resonance spectra. Stability of AgNPs was characterized by zeta potential measurements proving that amide and ester gemini surfactant series are able to effectively stabilize AgNPs. The particles size analysis utilizing dynamic light scattering and scanning electron microscopy showed that AgNPs stabilized with flexible ester-based gemini surfactants have their size smaller than those capped with amide-containing gemini surfactants. Antimicrobial and anti-inflammatory activity determination as well as cytotoxicity experiments with gemini surfactant stabilized AgNPs showed a complex dependence of biological activity of AgNPs on the molecular structure of stabilizing agents.

Cationic Gemini surfactants: a review on synthesis and their applications

Abstract The molecules of Gemini surfactants are dimeric and consist of two monomeric surfactant units linked by a spacer. Among them, cationic Gemini surfactants have a wide range of application in various industrial sectors such as pharmaceuticals, home and personal care, corrosion inhibition, etc. Various methods of synthesis have been investigated and tested for the synthesis of cationic Gemini surfactants. The surface properties of Gemini surfactants are highly dependent on various factors like spacer, headgroups, counterions, etc. The cationic Gemini surfactants have lower CMC values as compared to their monomeric analogues. This review highlights the different methods for the synthesis of cationic Gemini surfactants and the applications of these surfactants in different fields are presented.

Aggregation behavior of newly synthesized Gemini cationic surfactants in absence and in presence of different inorganic salts in 15% DMSO–water solvent

In this study, three Gemini cationic surfactants related to thiazol-2-amine with three hydrocarbon chain lengths including 3-hexylthiazol-3-ium (TAC6), 3-dodecylthiazol-3-ium (TAC12) and octadecylthiazol3-ium (TAC18) were prepared. Surfactant structures were confirmed with IR and 1HNMR Spectroscopies. Critical micelle concentrations for all surfactants in 15% DMSO-Water solvent were measured using conductometric, refractometric, and densitometric techniques. Thermodynamics parameters were computed and explained. Also, enhancing properties of all surfactants were indicated under the effect of two concentrations, 0.001 M and 0.01 M, of six inorganic salts including Cl−, Br−, I−, Co+2, Cu+2, and Mn+2 radicals using conductivity and refractive index measurements. All techniques used to measure critical micelles concentration showed a good convergence in measuring CMC values and the behavior of all surfactants in 15% DMSO-water solvent. Increasing the binding constant of the counter ion and association constant reflects the effect of hydrocarbon chain length increment on enhancing micelle formation, where TAC 18 was shown as the lowest CMC in all applied measurements. Modeling the density of all surfactant solutions under study indicates an increase in hydrophobic polarizability with an increase in the molecular weight of the surfactant. Inorganic salts decreased the CMC of all surfactants with the increase in Gibbs free energy of micellization which ensures easier formation of more stable micelles in the presence of a salt solution. The effect of salts on decreasing CMC for all surfactants under study was arranged in the following order: Mn+2 < Cu+2 < Co+2 for cationic radicals and I− < Br− < Cl− for anionic radicals.

Synthesis of Newly Ester Type Gemini Cationic Surfactants: Surface Properties, Fabric Softness and Antibacterial Properties

AbstractFour ester cationic Gemini surfactants (EDQ‐n, n represents the carbon number in the raw fatty acid of 12, 14, 16 and 18) were synthesized from fatty acid, N, N‐dimethylethanolamine and 1, 4‐dibromobutane by two‐step reaction of esterification and quaternization. Their surface activities at air/water interface were investigated. The application performance such as water solubility, antistatic property, fabric softness, fabric whiteness, biodegradability, and antibacterial activities were tested and compared with traditional quaternary ammonium salt. The results showed that the γcmc increases with increasing the hydrophobic chain length and EDQ‐12 presented the highest surface activity. The diffusion coefficients calculated from the Ward‐Tordai equation indicates the adsorption process is a mixed‐diffusion kinetic adsorption mechanism. The water solubility of EDQ‐n is higher than dioctadecyl dimethyl ammonium chloride (D1821) and ester quaternary ammonium salt (Esterquats). The fabric softness and whiteness properties of EDQ‐16 and EDQ‐18 are similar to D1821 and Esterquats, which can significantly reduce the cotton fabric softness and have no significant difference in whiteness retention. EDQ‐n demonstrated more readily biodegradation(&gt;90 %) than D1821(0 %) after seven days. In addition, EDQ‐12 and EDQ‐14 show excellent antibacterial activities against Staphylococcus aureus and Escherichia coli in comparison with conventional bacteriostatic agent didecyl dimethyl ammonium chloride (DDAC).

Investigation of micellization and thermodynamic properties of cationic gemini surfactant (12-2-O-2-12) in the presence of organic solvents

The micellization behaviour and thermodynamic properties of synthesized cationic gemini surfactant (12-2-O-12-12), N,N′-didodecyl-N,N,N′,N′-tetramethyl-N,N′-(oxybis(ethane-2,1-diyl))-diammonium dibromide were studied in the presence of organic solvents for four different temperatures (25, 30, 35 and 40 °C). Aqueous solutions of 10 % and 20 % methanol (MeOH), ethanol (EtOH), isopropanol (IPOH) and dimethyl sulfoxide (DMSO) were used as solvents. The critical micelle concentration (CMC) of cationic gemini surfactant and the degree of counterion dissociation (α) were determined by the conductometric method. Using the CMC and α values for each of the four temperatures, the values of the standard Gibbs free energy (ΔGmo), Gibbs free energy of transfer (ΔGm,transo), enthalpy (ΔHmo), and entropy (ΔSmo) of micellization were calculated. It was observed that the CMC and α values increased with increasing solvent percentage and temperature. It was found that in all cases, the standard Gibbs free energy and enthalpy values were negative while both the micellization entropy and the standard Gibbs free energy of transfer are positive. Negative Gibbs free energy values indicated that micellization was a spontaneous situation, while positive entropy values indicated the existence of a disordered situation. The positive ΔGm,transo values show that the presence of solvents makes the environment unfavorable for micelle formation.

Gemini cationic surfactant of 1, 3-bis (dodecyl dimethyl ammonium chloride) propane as a novel excellent inhibitor for the corrosion of cold rolled steel in HCl solution

Gemini surfactants have become the research focus of novel excellent inhibitors because of their special structure (two amphiphilic moieties covalently connected at head group by a spacer) and excellent surface properties. It is proved by theoretical calculations that 1, 3-bis (dodecyl dimethyl ammonium chloride) propane (BDDACP) molecules can perform electron transfer with Fe (110). And it has a small fraction free volume, thus greatly reducing the diffusion and migration degree of corrosive particles. The potentiodynamic polarization curve showed that coefficients of cathodic and anodic reaction less than 1 and polarization resistance increased to 1602.9 Ω cm−2 after added BDDACP, confirming that BDDACP significantly inhibited the corrosion reaction by occupying the active site. The electrochemical impedance spectrum of imperfect semi-circle shows that the system resistance increases and double layer capacitance after added BDDACP. Weight loss tests also confirmed that BDDACP forms protective film by occupying the active sites on steel surface, and the maximum inhibition efficiency is 92 %. Comparison of the microscopic morphology showed that steel surface roughness was significantly reduced after added BDDACP. The results of time-of-flight secondary ion mass spectrometry show that steel surface contains some elements from BDDACP, which confirms the adsorption of BDDACP on steel surface.

Effect of linking group on the corrosion inhibition performance of triazine-based cationic Gemini surfactants: Experimental and theoretical investigation

Three kinds of triazine-based cationic Gemini surfactants (TCGSII, TCGSIV and TCGSVI) with different lengths of the linking group were synthesized and characterized by FT-IR, 1H NMR and ESI-MS. The surface activity test showed that the surface activity of the surfactants decreased with the increase in the length of the linking group from 2 to 6. At the same concentration, the corrosion inhibition rate decreased with the increase in the length of the linking group, decreasing in the following order: TCGSⅡ > TCGSⅣ > TCGSⅥ. The corrosion inhibition effect of 0.2 mM TCGSⅡ reaches 98.03 %. The adsorption of the synthesized surfactants on the surface of carbon steel conforms to the Langmuir adsorption isotherm, and included physisorption and chemisorption on the metal surface. Quantum chemical calculations and molecular dynamics simulations verify this conclusion.

Structural Characteristics, Electronic Properties, and Coupling Behavior of 12-4-12, 12-3-12, 12-2-12 Cationic Surfactants: A First-Principles Computational Investigation and Experimental Raman Spectroscopy

In this study, we present a comprehensive first-principles computational investigation focused on the structural characteristics, electronic properties, and coupling integrations of three cationic Gemini surfactants: 12-4-12, 12-3-12, and 12-2-12 ((CH3(CH2)11)(CH3)2-N+-(CH2)n-N+(CH3(CH2)11)(CH3)2, where n = 2, 3, or 4). By employing Density Functional Theory (DFT) computations, we aimed to gain insights into the fundamental aspects of these surfactant molecules, and the intermolecular interactions among these surfactant molecules. We examined different conformers of each surfactant, including parallel, wing, and bent conformers, and compared their relative stability and properties. We elucidated that the complex structural characteristics, electronic properties, and molecular arrangements of the surfactants vary according to the number of carbon atoms in the central spacer. We also conducted experimental Raman spectroscopy on the three surfactants to compare the results with our computational findings. Furthermore, we computed the coupling behaviors of different conformers of 12-4-12 surfactants in order to gain insights into their coupling mechanism.

New Cationic Gemini Surfactants and Their Use as Dispersants in Oil-in-Water (O/W) Emulsions

In the current research, two types of new cationic gemini surfactants with different spacers (aromatic and heterocyclic) derived from epichlorohydrine were prepared. The prepared compounds were characterized using FTIR and 1H-NMR spectroscopy. Then the value of critical micelle concentration CMC was calculated using the electrical conductivity and preparing a series of molar concentration of the new surfactants, as well as calculating the balance value between the hydrophilic and hydrophobic (lipophilic) HLB groups. Cationic gemini surfactants were tasted at different concentration 20-40 ppm by preparing dishes for oil-in-water emulsions determine their dispersion efficiency. It was observed that the dispersant containing the heterogeneous ring (MS1) was more efficiently dispersed than the surfactant containing the aromatic ring (MS2) in the presence of the same hydrocarbon chain and at a concentration of 40 ppm.

Effect of cationic Gemini surfactants ethonium and decamethoxin on the spectral properties, solubility and tautomerism of the curcumin

AbstractThe properties of natural polyphenol curcumin in water solutions of cationic Gemini surfactants decamethoxin and ethonium, which have similar positively charged nitrogen hydrophilic head groups but different spacer sizes and lengths of hydrophobic tails have been investigated in a wide range of concentrations by using UV–Vis spectroscopy and quantum‐chemical calculations. It was found that curcumin dissolves in the organized micellar media of these surfactants in the enol tautomeric form and its solubility increases 400 times compared to water. The binding constants of curcumin with decamethoxin and ethonium were determined by the solubility method. Significant differences in the influence of premicellar concentrations of cationic Gemini surfactants on the solubility and tautomeric transformations of curcumin were revealed. In contrast to decamethoxin, ethonium at a concentration below the CMC promotes a significant increase in the solubility of curcumin and a shift in the tautomeric equilibrium towards the formation of its keto form.

Micellization, aggregation, interaction, and solubilization behaviors of mixed solutions of cationic gemini and nonionic surfactants

AbstractThe micellization properties of mixed aqueous solutions of a cationic gemini surfactant (CGS) and Triton X‐100, a conventional non‐ionic surfactant, with various mole fractions, were determined by measuring the surface tension at different temperatures. Various theoretical models were used to analyze the behavior of this mixed system. The interactions between CGS and Triton X‐100 were determined to be non‐ideal and synergistic. The calculated interaction parameters (βM) have negative values at all temperatures and for all mole fractions, showing attractive interactions. It was found that increasing the mole fraction of Triton X‐100 significantly increased the synergistic effect (more negative values). Micellar aggregation number (Nagg) values of pure surfactants and their mixtures in different ratios were obtained with the steady‐state fluorescence quenching method. Furthermore, the molar solubilization ratio of Sudan III organic dye in all surfactants aqueous systems was obtained using UV–Visible spectrophotometry. At concentrations above critical micelle concentration, the solubility of Sudan III in water was substantially increased linearly for all systems and it was observed that the enhancement was even more significant for mixed surfactant systems.

Molecular interaction of human serum albumin with gemini surfactant, 1,6 bis (N,N-hexadecyl dimethyl ammonium) bromide: Influence of micelles and pH

The interaction between human seram albumin (HSA) and a cationic gemini (dimeric) surfactant, 1,6 bis (N,N-hexadecyl dimethyl ammonium) bromide (16–6-16) has been investigated. Various analytical techniques, including UV–vis spectroscopy, fluorescence spectroscopy, lifetime fluorescence measurement, circular dichroism (CD), and atomic force microscope (AFM), were employed to investigate these interaction studies. The experiments were conducted in aqueous environments at three distinct pH levels (viz., below (4.0), at (4.7), and above (7.0) the isoelectric point (IP)), as well as both above and below the critical micellar concentration (CMC) of the surfactant (16–6-16). In these experimental conditions, HSA experiences conformational changes, leading to unfolding and denaturation as a result of its interaction with the gemini surfactant molecules (16–6-16). The extent of these conformational changes is found to be associated with both the degree of surfactant partial intercalation and the characteristics (size and charge) of the surfactant aggregates formed. The AFM microscopy studies provide insights into the topographical structural alterations occurring above, at, and below the CMC. Molecular docking analysis further validates the interaction between the protein (HSA) and the gemini surfactant (16–6-16) at a molecular level.

Performance of new synthesized emulsifiers in ecofriendly metal cutting fluid formulations

This study aims to prepare mono and gemini nonionic emulsifiers differing in HLB to utilize in formulated metal cutting fluids. Also, the cationic gemini surfactant (GCS) was prepared and applied as a corrosion inhibitor and biocide in the formulations. FT-IR and NMR confirmed the chemical structure of the prepared compounds. Different oil package formulations were prepared by adding different trial concentrations of the additives (emulsifier, corrosion inhibitor, coupling agent, and biocide) to the eco-friendly vegetable oil (castor oil). Standard procedures were performed to assess the stability of the formulated base oil packages. Six Formulas demonstrated the greatest oil stability. Oil in water emulsions with varying formulated oil ratios (5–15 wt%) were prepared. A standard test was carried out to evaluate their performance as emulsion stability. It’s been demonstrated that Formulas II and V produced stable emulsions. The wettability alteration of formulas II and V on different metal surfaces was evaluated. The droplet size of formulated castor oil in water was determined via DLS. Corrosion test and tribological properties were also performed. The findings of this study indicate that Formula V is a good choice as a renewable addition for enhancing a variety of performance characteristics of the water-based cutting fluid.

Selective and Efficient CO2 Electroreduction to Formate on Copper Electrodes Modified by Cationic Gemini Surfactants

AbstractElectroreduction of CO2 into valuable chemicals and fuels is a promising strategy to mitigate energy and environmental problems. However, it usually suffers from unsatisfactory selectivity for a single product and inadequate electrochemical stability. Herein, we report the first work to use cationic Gemini surfactants as modifiers to boost CO2 electroreduction to formate. The selectivity, activity and stability of the catalysts can be all significantly enhanced by Gemini surfactant modification. The Faradaic efficiency (FE) of formate could reach up to 96 %, and the energy efficiency (EE) could achieve 71 % over the Gemini surfactants modified Cu electrode. In addition, the Gemini surfactants modified commercial Bi2O3 nanosheets also showed an excellent catalytic performance, and the FE of formate reached 91 % with a current density of 510 mA cm−2 using the flow cell. Detailed studies demonstrated that the double quaternary ammonium cations and alkyl chains of the Gemini surfactants played a crucial role in boosting electroreduction CO2, which can not only stabilize the key intermediate HCOO* but also provide an easy access for CO2. These observations could shine light on the rational design of organic modifiers for promoted CO2 electroreduction.

Selective and Efficient CO2 Electroreduction to Formate on Copper Electrodes Modified by Cationic Gemini Surfactants.

Electroreduction of CO2 into valuable chemicals and fuels is a promising strategy to mitigate energy and environmental problems. However, it usually suffers from unsatisfactory selectivity for a single product and inadequate electrochemical stability. Herein, we report the first work to use cationic Gemini surfactants as modifiers to boost CO2 electroreduction to formate. The selectivity, activity and stability of the catalysts can be all significantly enhanced by Gemini surfactant modification. The Faradaic efficiency (FE) of formate could reach up to 96 %, and the energy efficiency (EE) could achieve 71 % over the Gemini surfactants modified Cu electrode. In addition, the Gemini surfactants modified commercial Bi2 O3 nanosheets also showed an excellent catalytic performance, and the FE of formate reached 91 % with a current density of 510 mA cm-2 using the flow cell. Detailed studies demonstrated that the double quaternary ammonium cations and alkyl chains of the Gemini surfactants played a crucial role in boosting electroreduction CO2 , which can not only stabilize the key intermediate HCOO* but also provide an easy access for CO2 . These observations could shine light on the rational design of organic modifiers for promoted CO2 electroreduction.

Synthesis, Characterization and In Vitro Anti-cancer Properties of Cationic Gemini Surfactants with Alkyl Chains in Human Breast Cancer

Gemini surfactants have unique advantages in various industries such as detergents, cosmetics, paints, and pharmaceuticals due to their versatile hydrophilic-lipophilic balance. Three novel cationic surfactants, derived from alkyl alcohol and epichlorohydrin, featuring multi-alkyl multiple quaternary-ammonium salts, were synthesized with the order of C4 &gt; C6 &gt; C8 alkyl groups. The structure of the synthetic compounds was determined using FTIR and 1H-NMR analysis. The anti-cancer properties of the Gemini surfactants were determined with the MCF-7 breast cancer cell line, using the MTT cytotoxicity assay. We found an increase in alkyl groups (C4 &gt; C6 &gt; C8), indicating that larger alkyl groups contribute to improved surface qualities. The compounds showed improved surface qualities and reduced critical micelle concentration (CMC). In addition, The results showed the significant anti-cancer potential of compound B1 on the breast cancer cell line. In comparison to compounds B2 and B3, the highest inhibition was observed at concentrations from 25 to 400 µg/mL, demonstrating 26.8% to 4.3% and 32% to 4.7%, inhibition, respectively.

Insights on Gemini cationic surfactants influence AgNPs synthesis: Controlling catalytic and antimicrobial activity

We engineered various surfactants by altering their hydrophobic properties, adjusting tail length. These changes significantly impacted their surface and thermodynamic characteristics in solution. Higher hydrophobicity led to a lowered critical micelle concentration (CMC), indicating increased surface adsorption. Among the gemini amphiphiles we synthesized, the one with the longest hydrophobic tail exhibited the lowest CMC of 0.58 mM and the highest ΔG°ads of −65.91 kJ.mol−1 at 20 °C. Elevated temperatures decreased CMC, enhancing both micellization and adsorption affinity. The surfactants, acting as capping agents during AgNPs preparation, influenced uniformity, stability, and size of the resulting AgNPs based on their hydrophobicity. Particularly, those with higher hydrophobicity resulted in smaller, stable AgNPs (10.1 ± 3.4 nm) compared to those with lower hydrophobicity. A clear link between surfactant hydrophobicity and the catalytic activity of AgNPs was evident. AgNPs derived from highly hydrophobic surfactants exhibited superior catalytic performance compared to those from less hydrophobic surfactants, showing efficient activity in converting methylene blue at −0.15 min-1 with a 20 μL dose. Moreover, the integration of AgNPs into surfactants displayed improved antibiotic activity against tested microbes, demonstrating exceptional efficacy, even surpassing common commercial antimicrobial agents.