Surfactant Chain Research Articles

Potential of Using Surfactants to Enhance Ammonium and Nitrate Adsorption on Rice Husk and Its Biochar

Inorganic nitrogen fertilizers are widely and heavily used in agriculture. Leaching of these fertilizers is a cause of eutrophication in water bodies. This study examines the use of rice husk and its biochar, their efficiency in adsorption of ammonium and nitrate and the potential of using surfactants, sodium dodecyl benzenesulfonate (SDBS) and cetyl trimethyl ammonium bromide (CTAB), to increase adsorption. Physical and chemical properties of adsorbents were examined through BET, SEM-EDX, and CEC value, respectively. The equilibrium batch adsorption was conducted. The result showed that rice husk was lower in surface area, total pore volume, pore diameter, silica and oxygen content, and CEC value as compared to biochar. Rice husk adsorbed nitrate well while rice husk biochar adsorbed ammonium ions better. The adsorption patterns of both ammonium and nitrate were well explained by Freundlich’s isotherm and are primarily attributed to chemical charge sorption. Both adsorbents could adsorb surfactants through Van der Waals forces between the long chain of surfactant and organic fraction on the surface of rice husks, exposing the charging head for ionic pollutant adsorption. Either SDBS or CTAB-modified rice husk and its biochar could enhance the adsorption of ammonium and nitrate.

The Influence of Surfactant Structure and Geometry on Nanotoxicity and Dispersion of Carbon Nanotubes

Graphene, nanotubes and fullerenes, also known as carbon nanomaterials (CN), because of the their unique properties have potential applications not only in preparation of new composite materials or in electronics, but they can be also components of drug delivery systems. However, the applications of CN in life sciences or biomedicine require stable dispersions of these materials in water. The hydrophobic nature of CN causes serious problems with their separation in water solutions. Our study is aimed to find a way of dispersing such CN systems in water, by the use of non-covalent surface modification via different surfactants. In this work we focused on the use of trimeric, dimeric and monomeric surfactants fornon-covalent surface modification of selected carbon nanotubes. The toxicity of these systems (aqueous solutions of CN with surfactants and surfactants solutions) towards selected cell cultures (e. g. HeLa cells) was also tested. The surfactants studied can interact with carbon nanotubes in a number of different modes: hydrophobic interactions (surfactant chains with CN side walls) or π-π interactions (aromatic rings of surfactants with CN surface). Infrared spectroscopy and atomic force microscopy were used for characterization of the systems studied. Finally, we focused on mechanical properties of cells exposed to surfactants and CN. This study was supported by the Ministry of Science and Higher Education (Poland), within the project “Najlepsi z najlepszych!” (DEC - POWR.03.03.00-00-P001/15).

Enhanced adsorption capacity of dyes by surfactant-modified layered double hydroxides from aqueous solution

Abstract The utilization of organo-modified layered double hydroxides with anionic surfactants (organo-LDHs) as adsorbents were successfully carried out to remove various synthetic dyes from aqueous solution. Intercalation of anionic surfactants changed the surface properties of MgAl-LDH from hydrophilic to hydrophobic, and a charge inversion occurred with increasing the length of surfactant chains. Such changes in the surface properties of the organo-LDHs were important. Experimental data shown that the SNS-modified MgAl-LDH could be used as a broad-spectrum adsorbent to effectively remove anionic, non-ionic, and cationic dyes from aqueous solution.

Hydrophilicity and flexibility of the spacer as critical parameters on the aggregation behavior of long alkyl chain cationic gemini surfactants in aqueous solution

Abstract Series of quaternary ammonium-based gemini surfactants with long alkyl chains (C12 and C18) containing different spacers and substituents attached to the polar head group have been synthesized and their aggregation properties in aqueous solution examined. The effect of the hydrophobic chain, the nature and structure of the spacer group and the polarity of the head group on the aggregation behavior of such dimeric surfactants has been investigated. The critical micelle concentration (cmc) values of gemini surfactants in aqueous solution were determined by conductivity, steady state fluorescence and potentiometric measurements. The size of aggregates formed by investigated amphiphiles above the cmc in aqueous solution was examined by dynamic light scattering. Gemini surfactants show cmc values significantly lower than those of comparable single chain surfactants. The tendency of trimeric surfactants with a rigid spacer to form aggregates is higher than that of the corresponding dimeric surfactants. As occurs for monomeric ionic surfactants, the cmc of gemini surfactants decreases with the elongation of the hydrophobic chain. However, the effect of lengthening the alkyl chain on the cmc depends on the structure of the spacer. C12 gemini surfactants with a rigid hydrophobic spacer exhibit cmc higher than those containing a flexible hydrophobic spacer. For gemini surfactants with C18 alkyl chains this effect is even more pronounced and leads to differences in cmc values greater than one order of magnitude. The structure of the spacer, flexible or rigid chain, has been found to be a critical parameter on the self-assembly of long chain gemini surfactants. Spherical micelles are spontaneously formed above the cmc for C12 gemini surfactants, whereas trimeric and C18 gemini surfactants seems to form vesicle-like aggregates when self-aggregation occurs.

Fabrication of metalosomes (metal containing cationic liposomes) using single chain surfactants as a precursor via formation of inorganic organic hybrids.

Among the self-assembled forms of surfactants, vesicles/liposomes are a highly promising and interesting feature of surfactants, which are usually formed from water insoluble surfactants. Herein, we demonstrate the formation of liposomes from single-chain cationic surfactants with the help of metals as a part of the counter ion, and these metal embedded liposomes are termed as metalosomes. It is a noteworthy advancement in the area of self-assembled molecular structures since we report the preparation of metal embedded liposomes (metalosomes) from a water soluble single chain cationic surfactant, which is otherwise a property or an arrangement made by double tailed surfactants, or more precisely lipids that are poorly water soluble. We can use this method for various cationic surfactants and metal combinations and the studies are still in process. However, this preliminary report on manganese-based surfactants depicts the successful formation of cationic metalosomes (with/without cholesterol), and the formation, structure and size has been verified using TEM, FE-SEM, DLS XRD and SAXS. The comparison of metalosomes with reverse vesicles in different solvents further gave an insight of microstructure and solvent environment effects on the self-assembly of metallosurfactants. In addition, we have also evaluated the encapsulation ability of metalosomes for fluorescein dye. High encapsulation efficiency of Mn-somes makes them promising candidates for several applications, particularly because of its water solubility.

Synthesis, physicochemical, and biological activities of novel N-acyl tyrosine monomeric and Gemini surfactants in single and SDS/CTAB-mixed micellar system

A series of single-chained N-acyl tyrosine surfactants with varying chain lengths (C10-C18) and degree of unsaturation, as well as an N-acyl Gemini tyrosine surfactant with chain length C12, were synthesized, and the structures were confirmed using spectral analysis. The effect of chain length and level of unsaturation on the physicochemical and antibacterial properties of the N-acyl tyrosine surfactants was evaluated. The C12 derivative displayed the optimum antibacterial activity among the single chain surfactants, and the presence of double bond in the oleoyl derivative enhanced the antibacterial activity over its saturated analogue. The N-acyl Gemini surfactant displayed the highest antibacterial activity among the series and also showed greater micelle forming ability than its single chain analogue. Mixed micellar behavior of the N-acyl Gemini surfactant with conventional cationic (CTAB) and anionic (SDS) surfactants in aqueous solution was studied. The negative value of the interaction parameter β12 observed for the N-acyl Gemini in binary mixture with CTAB surfactant indicated a synergistic interaction within the mixed micellar system. However, the binary mixture with SDS displayed antagonistic behavior. The binary mixture of N-acyl Gemini surfactant with CTAB displayed better antibacterial activity and foaming properties than with SDS mixtures. Optimum antibacterial activity was observed for N-acyl Gemini surfactant with mole ratio 0.4 to 0.6 in the CTAB binary mixture, at which the lowest ocular irritation index was observed. Overall, the study showed that the Gemini surfactant in combination with the conventional surfactant CTAB can be used as potential ingredients in detergent and pharmaceutical formulations.

Insight into thiabendazole interaction with montmorillonite and organically modified montmorillonites

The interactions of the fungicide, thiabendazole (TBZ) on montmorillonite (Mt) and organoclays synthesized from phosphatidylcholine (DSPC) and octadecyltrimethylammonium bromide (ODTMA) was investigated for water remediation. The affinity of TBZ on the surface of Mt and organoclays was evaluated by powder X-ray diffraction, X-ray photoelectron spectroscopy and the experimental results were also reinforced by molecular modelling in order to explore the surfaces arrangements. TBZ was protonated upon interaction with negative charged Mt and therefore this strong electrostatic interactions prevented it's desorption in water. Repulsive electrostatic interactions between the cationic surfactant ODTMA and the cationic form of TBZ on the outer surface of the ODTMA modified Mt resulted in high desorption values. In the DSPC modified Mt, TBZ was anchored within the surfactant chains and a small amount of interlayer water was released from the interlayer space.

Organoclay-based nanoparticles from montmorillonite and natural clay deposits: Synthesis, characteristics, and application for MTBE removal

This study introduces organoclay-based submicron- and nanosized particles prepared from montmorillonite (SWy2) and naturally occurring clay deposits using sequential steps of wet ball milling, ultrasonication and sedimentation followed by an ion exchange process using two surfactants, long alkyl chain HDTMA+ (hexadecyltrimethylammonium bromide) and short alkyl chain TMA+ (tetramethylammonium bromide). The resultant organoclay-based nanoparticles were characterized using X-ray diffraction (XRD), thermogravimetric-differential thermal analysis (TG-DTA) and Fourier-transform infrared (FTIR) spectroscopy. The adsorption of MTBE (methyl tert-butyl ether) by organo-montmorillonite with different surfactant loadings (0.5–2.0 CEC) in aqueous solution was also investigated. The results of XRD analysis for organoclay-based nanoparticles showed that the value of d (001) increased with increasing alkyl chain length and surfactant loading. FTIR results showed that the functional groups of the organoclays changed due to the intercalation of the long alkyl chain surfactant HDTMA+ between clay layers. The removal of MTBE is highly dependent upon surfactant type and loading. The results indicated that the organo-montmorillonite-based nanoparticles prepared from HDTMA+ have a higher affinity for MTBE in aqueous solution than the organo-montmorillonite prepared from TMA+. Therefore, long alkyl chain HDTMA+ can be considered to be the most suitable organo-modifier for enhancing the adsorption characteristics of montmorillonite for MTBE removal.

Synthesis of PANI solid microspheres with convex-fold surface via using polyvinylpyrrolidone micellar template

Although various micro/nanostructures of polyaniline (PANI) have been reported, it still remains as a great challenge to produce PANI solid microspheres. Here, with the aid of polyvinylpyrrolidone (PVP) micellar template, PANI solid microspheres with convex-fold surface are readily prepared in a static HCl solution (0.010M) at room temperature. The measured results of SEM, TEM, FTIR, XRD, XPS, and TGA demonstrate the successful preparation of PANI microspheres having solid structure. Moreover, the effects of concentration of HCl solution and surfactant types on the morphologies of PANI structures are investigated. The trick of forming such solid microspheres is ascribed to the synergistic effect of appropriate concentration of dopant acid, specific surfactant, and long alkyl chain of PVP molecules which has better solubilization effect on aniline molecules in comparison with other organic acid micellar templates.

Foamability of fatty acid solutions and surfactant transfer between foam and solution phases

The foaming properties of aqueous solutions of fatty acids with different hydrocarbon chain lengths - hexanoate, laurate, and oleate - were assessed through measurements of foam volume and growth rate under continuous aeration. Simultaneous measurements of the partition of each surfactant between the bulk solution and foam phases were also carried out. Although bubble size measurements in bulk solution pointed towards quite similar gas dispersing abilities of the tested surfactants, their foamabilities under the same conditions were remarkably enhanced with increasing chain length of the hydrocarbon tail. Shorter chain surfactants - hexanoate and laurate - generated wet foams and the accumulation of these surfactants in the foam phase was very low, indicative of a low adsorption density of the reagents at the gas-liquid interface. In contrast, sodium oleate produced stable dry foams, and the amount of oleate transferred to the foam was much higher. The formation of these different types of foam was attributed to the higher adsorption of oleate at the gas-liquid interface compared to the lower adsorption of hexanoate or laurate, and to different mechanisms of foam stabilization. Regardless of the interfacial mechanism of the foaming action of the tested surfactants, it was generally found that strong foaming was possible only from surfactant solutions whose bulk concentration was higher than the critical coalescence concentration of a given surfactant. It was concluded that bubbles entering the foam phase from the bulk solution phase must already be stable against coalescence to induce foam formation and impart stability to the entire foam column. Foaming was observed only in true solutions of the tested surfactants, while precipitation of colloidal acid species completely depressed foam formation.

Modified inverse micelle synthesis for mesoporous alumina with a high D4 siloxane adsorption capacity

In this work, mesoporous aluminas (MAs) with uniform and monomodal pores were fabricated via a modified inverse micelle synthesis method, using a non-polar solvent (to minimize the effect of water content) and short reaction time (for a fast evaporation process). The effects of reaction times (4–8 h), surfactant chain lengths (non-ionic surfactants), and calcination temperatures and hold times (450–600 °C; 1–4 h) on the textural properties of MA were studied. The targeted pore sizes of MA were obtained in the range of 3.1–5.4 nm by adjusting the surfactant and reaction time. The surface area and pore volume were controlled by the calcination temperature and hold time while maintaining the thermal stability of the materials. The tuned MA of the large mesopore volume achieved 168 mg/g octamethylcyclotetrasiloxane (D4 siloxane) adsorption capacity, a 32% improvement compared to commercially activated alumina. After three adsorption recycles, the synthesized MA still maintained approximate 85% of its original adsorption capacity, demonstrating a sustainable adsorption performance and high potential for related industrial applications.

Investigation on the gelatin-surfactant interaction and physiochemical characteristics of the mixture

Gelatin assisted micellization of polyoxyethylatedhexadecyl ethers. • The formation of a surface-active gelatin-surfactant complex was suggested. • The parking area of surfactant monomer increased with increase in gelatin amount. • The stepwise growth of the micelle in presence of gelatin was confirmed. • The protruded surfactant chains entwined over gelatin moiety at the interface. • The size of BC-X micelles decreased with increase in gelatin amount in the mixture.

Double-Tailed Cystine Derivatives as Novel Substitutes of Phospholipids with Special Reference to Liposomes.

Cystine-based gemini surfactants with dodecyl, tetradecyl, hexadecyl, and octadecyl hydrocarbon chains were synthesized, and their interactions with unsaturated (soy phosphatidylcholine, SPC)/saturated (hydrogenated SPC, HSPC) soy phosphatidylcholines in the forms of a monolayer and a model liposome were estimated for different combinations of the components in the mixed systems. Studies of Langmuir monolayers at the air-aqueous buffer interface revealed condensation of the monomolecular films with the addition of surfactants. The effect of surfactants decreased according to the following order: octadecyl > hexadecyl > tetradecyl > dodecyl homologs. The nonideal mixing between the components was estimated using the deviation of the experimental molecular area from the ideal area per molecule. The excess molecular area increased with the increase in the surfactant chain length and phospholipid saturation. The 50 mol % mixture of cystine derivatives and phospholipids formed thermodynamically stable monolayers. The surfactants increased the rigidity of SPC monolayers and decreased that of HSPC monolayers, as observed by the studies of surface dialational rheology. The film structure at the air-water interface could differentiate the SPC- and HSPC-comprising systems through the formation of organized regions, especially at a higher surface pressure. The constriction of surfactant/phospholipid hybrid vesicles was observed with an increase in the length of surfactant hydrocarbon chains. The negative zeta potential of vesicles took the highest values and did not change with time for 20 and 50 mol % surfactant. The spherical shape of the vesicles was confirmed by transmission electron microscopy. Differential scanning calorimetry revealed an increase in fluidity of HSPC bilayers and rigidity of SPS bilayers under the influence of surfactants. These effects were confirmed by fluorescence spectroscopy. All of the vesicle formulations were found to be nontoxic from the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide assay, suggesting their potential as a novel membranous system for the delivery of drugs, genetic materials, vaccines, and other therapeutic agents.

The effect of surfactant chain length on the morphology of poly(methyl methacrylate) microcapsules for fragrance oil encapsulation

The solvent evaporation method for producing microcapsules relies upon the correct wetting conditions between the three phases involved in the synthesis to allow core-shell morphologies to form. By measuring the interfacial tensions between the oil, polymer and aqueous phases, spreading coefficients can be calculated, allowing the capsule morphology to be predicted. In this work we explore the effect of surfactant chain length on capsule morphology using poly(methyl methacrylate) as the polymer and hexadecane as the core. We compared the predicted morphologies obtained using the polymer as a solid, and the polymer dissolved in dichloromethane to represent the point at which capsule formation begins. We found that using the polymer in its final, solid form gave predictions which were more consistent with our observations. The method was applied to successfully predict the capsule morphologies obtained when commercial fragrance oils were encapsulated.

Adsorption, Ordering, and Local Environments of Surfactant-Encapsulated Polyoxometalate Ions Probed at the Air-Water Interface.

The continued development and application of surfactant-encapsulated polyoxometalates (SEPs) relies on understanding the ordering and organization of species at their interface and how these are impacted by the various local environments to which they are exposed. Here, we report on the equilibrium properties of two common SEPs adsorbed to the air-water interface and probed with surface-specific vibrational sum-frequency generation (SFG) spectroscopy. These results reveal clear shifts in vibrational band positions, the magnitude of which scales with the charge of the SEP core, which is indicative of a static field effect on the surfactant coating and the associated local chemical environment. This static field also induces ordering in surrounding water molecules that is mediated by charge screening via the surface-bound surfactants. From these SFG measurements, we are able to show that Mo132-based SEPs are more polar than Mo72V30 SEPs. Disorder in the surfactant chain packing at the highly curved SEP surfaces is attributed to large conic volumes that can be sampled without interactions with neighboring chains. Measurements of adsorption isotherms yield free energies of adsorption to the air-water interface of -46.8 ± 0.4 and -44.8 ± 1.2 kJ/mol for the Mo132 and Mo72V30 SEPs, respectively, indicating a strong propensity for the fluid surface. The influence of intermolecular interactions on the surface adsorption energies is discussed.

SURFACTANT INDUCED INTERFACIAL ANCHORING TRANSITIONS IN NEMATIC LIQUID CRYSTAL DROPLETS ON GLASS SURFACES

The interfacial adsorption of surfactants at planar nematic liquid crystal (NLC)–water interface induces an ordering transition from a tilted to perpendicular anchoring with the increase in surfactant concentration at [Formula: see text], where [Formula: see text] is the Critical Micelle Concentration of surfactants in water. In this study, we show that depending upon the surfactant structure a tilted to perpendicular NLC anchoring transition is observed at [Formula: see text] in 5CB droplets of size 50–70[Formula: see text][Formula: see text]m. Micrometer sized 5CB droplets are deposited on glass surfaces using flow coating of 5CB-in-ethanol solutions. When placed on 5CB drop decorated glass surfaces, the aqueous surfactant solutions of aliphatic chain surfactants (SDS, CTAB and CPBr) at [Formula: see text], result in an optical transition to a bright-cross texture attributed to the tilted anchoring of 5CB molecules at 5CB–water interface. At [Formula: see text], perpendicular anchoring of 5CB molecules at 5CB–water interface results in a droplet texture with a hedgehog defect. In contrast, aqueous solutions of SDBS lead to 5CB droplets with a bright-cross texture regardless of the surfactant concentration in the aqueous phase. These results indicate that the orientation of 5CB molecules is independent of the nature of the surfactant headgroup. In addition, 5CB droplet decorated OTS treated glass substrates show a hedgehog texture which disappears completely on exposure to organic vapors with the response time-dependent on the polarity of the vapor molecules.

Effect of anionic surfactants on the stability ratio and electrophoretic mobility of colloidal hematite particles

The effect of anionic surfactants on the charging and aggregation of hematite particles was investigated. Charging behavior was studied by the measurement and analysis of the electrophoretic mobility. The stability ratio of hematite suspension was obtained from the temporal change of turbidity, and the stability ratio was analyzed by the DLVO theory. These experiments were performed as functions of types of surfactant, surfactant dosage, and surfactant chain length. Electrophoretic mobility of bare hematite was positive at pH below 7. The mobility went through zero and became negative with increasing surfactant dosage. Required surfactant concentrations reaching the isoelectric point decreased with increasing the chain length of surfactant. These results are reasonably described by a simple theoretical model. The stability ratio showed the minimum around the isoelectric point. That is, the suspension is destabilized by charge neutralization due to the adsorption of surfactants onto the hematite. Values of the minimum stability ratio in this work were almost unity irrespective of the chain length; the fastest aggregation rate with surfactants equaled the salt-induced rate. Therefore, in the case of ionic-surfactant, charge-patch attraction and steric hindrance do not significantly work around zero mobility concentration. The DLVO theory qualitatively describes the aggregation behavior. The range of the minimum stability ratio was narrower for the suspension with fatty acids. This result indicates that the suspension with fatty acids is more stable.

Influence of octanohydroxamic acid on the association behavior of cationic surfactants: Hydrolytic cleavage of phosphate ester

The surface properties and mixed micellization behavior of cetyltrimethylammonium bromide (CTAB), tetradecyltrimethylammonium bromide (TTAB) and dodecyltrimethylammonium bromide (DTAB) with octanohydroxamic acid (OHA) have been investigated by means of conductivity and surface tension measurements in aqueous solution and borate buffer at 300K. The critical micelle concentration (cmc), surface properties such as maximum surface access (Γmax), surface pressure at the cmc (Πcmc) and minimum surface area per molecule (Amin) has been determined. The standard Gibbs free energy of micellization (ΔGm0), standard Gibbs free energy of adsorption (ΔGad0), and standard Gibbs free energy of micellization per alkyl chain (ΔGm,tail0) of cationic surfactant with OHA have been evaluated. The fluorescence quenching technique was used to estimate the aggregation number (Nagg) and packing parameter (P) for determining the structural feature of cationic surfactants in the presence of octanohydroxamic acid. The hydrolytic reaction of paraoxon with octanohydroxamic acid was studied under a cationic micellar system by using OHA− at 9.2pH and 300K. The variations of surface properties from aqueous medium to the reaction condition have also been discussed. Pseudophase model (PPM) has been fitted for the quantitative treatment of the data.

Control of drop shape transformations in cooled emulsions

The general mechanisms of structure and form generation are the keys to understanding the fundamental processes of morphogenesis in living and non-living systems. In our recent study (Denkov et al., Nature 528 (2015) 392) we showed that micrometer sized n-alkane drops, dispersed in aqueous surfactant solutions, can break symmetry upon cooling and “self-shape” into a series of geometric shapes with complex internal structure. This phenomenon is important in two contexts, as it provides: (a) new, highly efficient bottom-up approach for producing particles with complex shapes, and (b) remarkably simple system, from the viewpoint of its chemical composition, which exhibits the basic processes of structure and shape transformations, reminiscent of morphogenesis events in living organisms. In the current study, we show for the first time that drops of other chemical substances, such as long-chain alcohols, triglycerides, alkyl cyclohexanes, and linear alkenes, can also evolve spontaneously into similar non-spherical shapes. We demonstrate that the main factors which control the drop “self-shaping”, are the surfactant type and chain length, cooling rate, and initial drop size. The studied surfactants are classified into four distinct groups, with respect to their effect on the “self-shaping” phenomenon. Coherent explanations of the main experimental trends are proposed. The obtained results open new prospects for fundamental and applied research in several fields, as they demonstrate that: (1) very simple chemical systems may show complex structure and shape shifts, similar to those observed in living organisms; (2) the molecular self-assembly in frustrated confinement may result in complex events, governed by the laws of elasto-capillarity and tensegrity; (3) the surfactant type and cooling rate could be used to obtain micro-particles with desired shapes and aspect ratios; and (4) the systems studied serve as a powerful toolbox to investigate systematically these phenomena.

Interfacial effects and emulsion stabilization by in situ surfactant generation through the saponification of esters

The stabilization of oil-in-water emulsions is critical for a wide variety of fields. Here, we explore the reaction dynamics of and emulsion stabilization by in situ surfactant generation through the saponification of esters that are commonly used in cosmetics and drug delivery. We combine measurements of dynamic interfacial tension and surface elasticity with emulsion stability to determine the dynamics of the interfacial reaction and its effect on interfacial properties. The rate of surfactant production through the in situ reaction depends on the surface area and thus the dynamics measured in a pendant drop may not reflect the dynamics in emulsification. To test this, we also measure the dynamics of surfactant production after emulsification. Further, we explore the effect of surfactant chain length and solution pH on the interfacial tension dynamics and the emulsion stability. The results show that the interfacial tension transients in a pendant drop correlate with the in situ reaction dynamics but that there are others factors to consider. The steady state interfacial tension represents a pseudo-steady state between rate of surfactant produced and that desorbing into the aqueous phase. The interfacial tension dynamics and emulsion stability also depend strongly on the charge. The emulsions retain stability after aqueous pH neutralization, suggesting that a portion of the adsorbed surfactant molecules remain ionized at neutral pH. Emulsion stability increases with increasing surfactant chain length, which is the expected trend because a longer chain length reduces aqueous solubility thereby increasing the surfactant surface coverage. Therefore, the approach of emulsion stabilization by in situ surfactant production is more useful for surfactants with very low aqueous solubility. Finally, the transients of surfactant concentration in the emulsions show a reduction in the rate of the in situ reaction with increasing coverage of the surface by the adsorbed anionic surfactant most likely due to the buildup of surface charge that reduces the concentration of the hydroxyl ions at the surface.