Cationic Surfactant Tetradecyltrimethylammonium Research Articles

Equilibrium and dynamic surface properties of cationic/anionic surfactant mixtures based on alcohol ether sulfate

The equilibrium and dynamic surface properties of anionic surfactant alcohol ether sulfate with different EO distribution(C-AE2S and N-AE2S) and cationic surfactant tetradecyltrimethylammonium bromide (TTAB) mixtures under different molar ratios were investigated. Their surface activities, adsorption, and spreading performances were investigated by static/dynamic surface tension measurements, molecular dynamics simulation, and dynamic contact angle techniques at 298 K. The static surface tension analysis reveals that the critical micellization concentration (cmc) values and the surface tension at cmc (γ cmc) of the binary systems are much lower than that of the individual component. Compared with C-AE2S/TTAB, N-AE2S/TTAB systems have higher cmc and lower γ cmc. It was found from the molecular dynamics simulation that negative charges of C-AE2S were drastically neutralized by the positively-charged TTAB at the interface in the system of C-AE2S/TTAB. The dynamic surface tension results indicate that the adsorption process of aqueous solutions for both C-AE2S/TTAB and N-AE2S/TTAB are mixed diffusion-kinetic adsorption mechanisms. From the dynamic contact angle measurements, it could be obtained that the mixtures exhibit better spreading behavior than that of the individual component and N-AE2S/TTAB systems have lower contact angles than that of C-AE2S/TTAB at the same mixing ratios.

Monitoring Gypsum Plaster Setting in a Foam through Raman Spectroscopy

We use Raman spectroscopy to probe in situ the hydration reaction of a foamed mineral binder, here gypsum plaster. We show the strong effect of the mixing process used for foaming on the hydration kinetics. On the contrary, we observe no effect of the cationic surfactant tetradecyltrimethylammonium bromide (TTAB) used as foaming agent and of the foam structure. By tuning the hydration time scale with a setting retardant (citric acid) and measuring in parallel the characteristic bubble radius in the foam, we show that hydration kinetics control the arrest of the bubble-size evolution in the fresh foam and the final pore size in the set gypsum.

Synergy of surface modified nanoparticles and surfactant in wettability alteration of calcite at high salinity and temperature

The surface of silica nanoparticles (NPs) was modified by chemical grafting of ligands to: (1) achieve colloidal stability in concentrated brine at salinities up to 25.7 % total dissolved solids (TDS) and temperatures up to 90 °C and (2) change the wettability of carbonate reservoirs from oil-wet to water-wet. The ligand precursors included low molecular weight cationic N-trimethoxysilylpropyl-N, N, N-trimethylammonium chloride or nonionic 3-glycidyloxypropyl trimethoxysilane. The water-phase contact angle θw of a crude oil droplet on calcite was measured for binary mixtures of the modified NPs combined with different types of surfactants, for a heavy and a light crude oil. For two types of reservoir conditions (16.7 % TDS at 55 °C and 25.7 % TDS at 90 °C), positively charged NPs with quaternary nitrogens (QNP) at 1 wt% altered the wettability of the calcite surface from strongly oil-wet (θw = 125° to 159°) to intermediate wet with a θw = 69° to 85° for light crude oil and θw = 71° to 107° for heavy crude oil. Meanwhile, cationic surfactants tetradecyltrimethylammonium bromide (TTAB) at 1 wt% altered the wettability to water-wet with a θw = 41° to 59° for light crude oil and θw = 70° to 90° for heavy crude oil. Synergy between the QNP and TTAB was observed in lowering the θw by another 10°. The reduced θw is beneficial for secondary oil recovery from carbonates, along with a significant decrease in the viscoelasticity of the crude oil-brine interface that helps destabilize undesirable water-in-crude oil emulsions.

A new model to describe small-angle neutron scattering from foams.

The modelling of scattering data from foams is very challenging due to the complex structure of foams and is therefore often reduced to the fitting of single peak positions or feature mimicking. This article presents a more elaborate model to describe the small-angle neutron scattering (SANS) data from foams. The model takes into account the geometry of the foam bubbles and is based on an incoherent superposition of the reflectivity curves arising from the foam films and the small-angle scattering (SAS) contribution from the plateau borders. The model is capable of describing the complete scattering curve of a foam stabilized by the standard cationic surfactant tetradecyltrimethylammonium bromide (C14TAB) with different water contents, i.e. different drainage states, and provides information on the thickness distribution of liquid films inside the foam. The mean film thickness decreases with decreasing water content because of drainage, from 28 to 22 nm, while the polydispersity increases. These results are in good agreement with the film thicknesses of individual horizontal foam films studied with a thin-film pressure balance.

Insights into Extended Structures and Their Driving Force: Influence of Salt on Polyelectrolyte/Surfactant Mixtures at the Air/Water Interface.

This paper addresses the effect of polyelectrolyte stiffness on the surface structure of polyelectrolyte (P)/surfactant (S) mixtures. Therefore, two different anionic Ps with different intrinsic persistence length lP are studied while varying the salt concentration (0-10-2 M). Either monosulfonated polyphenylene sulfone (sPSO2-220, lP ∼20 nm) or sodium poly(styrenesulfonate) (PSS, lP ∼1 nm) is mixed with the cationic surfactant tetradecyltrimethylammonium bromide (C14TAB) well below its critical micelle concentration and studied with tensiometry and neutron reflectivity experiments. We kept the S concentration (10-4 M) constant, while we varied the P concentration (10-5-10-3 M of the monomer, denoted as monoM). P and S adsorb at the air/water interface for all studied mixtures. Around the bulk stoichiometric mixing point (BSMP), PSS/C14TAB mixtures lose their surface activity, whereas sPSO2-220/C14TAB mixtures form extended structures perpendicular to the surface (meaning a layer of S with attached P and additional layers of P and S underneath instead of only a monolayer of S with P). Considering the different P monomer structures as well as the impact of salt, we identified the driving force for the formation of these extended structures: compensation of all interfacial charges (P/S ratio ∼1) to maximize the gain of entropy. By increasing the flexibility of P, we can tune the interfacial structures from extended structures to monolayers. These findings may help improve applications based on the adsorption of P/S mixtures in the fields of cosmetic or oil recovery.

Enhanced Corrosion Resistance of Layered Double Hydroxide Films on Mg Alloy: The Key Role of Cationic Surfactant.

In this study, dense anticorrosion magnesium–aluminum layered double hydroxide (MgAl-LDH) films were prepared for the first time by introducing a cationic surfactant tetradecyltrimethyl ammonium bromide (TTAB) in the process of in situ hydrothermal synthesis of Mg-Al LDH films on an AZ31 magnesium alloy. Results of XRD, FTIR, and SEM confirmed that TTAB forms the MgAl-LDH-TTAB, although TTAB cannot enter into LDH layers, and MgAl-LDH-TTAB powders are much smaller and more homogenous than MgAl-CO32−-LDH powders. Results of SEM, EDS, mapping, and XPS confirmed that TTAB forms the MgAl-LDH-TTAB films and endows LDH films with denser structure, which provides films with better shielding efficiency. Results of potentiodynamic polarization curves (PDP) and electrochemical impedance spectroscopy (EIS) confirmed that MgAl-LDH-TTABx g films have better corrosion resistance than an MgAl-CO32−-LDH film. The corrosion current density (icorr) of the MgAl-LDH-TTAB0.35 g film in 3.5 wt.% NaCl solution was reduced to 1.09 × 10−8 A.cm−2 and the |Z|f = 0.05 Hz value was increased to 4.48 × 105 Ω·cm2. Moreover, the increasing concentration of TTAB in MgAl-LDH-TTABx g (x = 0.025, 0.05, 0.1, 0.2 and 0.35) provided denser outer layer LDH films and thereby increased the corrosion resistance of the AZ31 Mg alloy. Additionally, the |Z|f = 0.05 Hz values of the MgAl-LDH-TTAB0.35 g film still remained at 105 Ω·cm2 after being immersed in 3.5 wt.% NaCl solution for 168 h, implying the good long-term corrosion resistance of MgAl-LDH-TTABx g films. Therefore, introducing cationic surfactant in the process of in situ hydrothermal synthesis can be seen as a novel approach to creating efficient anticorrosion LDH films for Mg alloys.

Interaction of an imidazolium based ionic liquid with antidepressant drugs: A physicochemical study

The effect of two antidepressant drugs i.e., CPZ and PMZ on the colloidal behaviour of 1-decyl-3-methyl-imidazolium tetrafluoroborate [Dmim][BF4] ionic liquid has been studied and compared with the structurally similar cationic surfactant tetradecyltrimethylammonium bromide (TTAB). The micellization and interfacial parameters of [Dmim][BF4] and TTAB, in the presence of antidepressant drugs have been determined using conductivity and surface tension measurements. The aggregation number (Nagg) and Stern-Volmer constant (Ksv) have also been determined by fluorescence measurements. Various micellar and interfacial parameters of drug-surfactant system (CPZ/PMZ+[Dmim][BF4]/ CPZ/PMZ+TTAB) indicates favourable interaction between them. The dynamic light scattering measurements have also been employed for the size of aggregates. This study concluded that imidazolium based ionic liquid could probably act as better drug carriers than conventional cationic surfactants.

Surfactant assisted synthesis of pH responsive polyaniline-cellulose biocomposite for sensor applications

ABSTRACT In the present communication, an anionic surfactant, sodium dodecylbenzenesulfonate (SDBS) and a cationic surfactant tetradecyltrimethylammonium bromide (TTAB) were employed as soft templates for the preparation of biocomposites of polyaniline and cellulose, PAni/Cell, via oxidation polymerization. These biocomposites were characterized by UV/Vis, Fourier Transform Infra red (FTIR), and X-ray diffraction (XRD) methods. Wire-like and porous structures are observed for PAni/Cell prepared in the presence of SDBS whereas, presence of TTAB shows clusters-like structures. Electrochemical properties displayed by cyclic voltammograms (CV) of PAni/Cell/surfactant electrode, the effect of scan rate, and pH on the current response indicate its compatibility in sensor applications.

Influence of TTAB/14-S-14 Micelles on the Rate of the Condensation between Ninhydrin and Mercury-Dipeptide Complex in Absence and Presence of Salts and Organic Solvents: A Kinetic Approach

The interaction of mercury(II)–glycyl-L-alanine [Hg(II)–Gly-L-Ala]+ complex with ninhydrin has been studied kinetically both in aqueous as well as micellar media (cationic conventional/gemini surfactants) using UV-vis spectrophotometer at 70 ºC and a particular pH 5.0. The study was carried out as functions of [Hg(II)–Gly-L-Ala]+, [ninhydrin], [surfactant] [salts], and solvents (%v/v). The first-order-rate is observed concerning [Hg(II)–Gly-L-Ala]+, whereas fractional-order-rate dependence for [ninhydrin]. It has been found that 14-s-14 geminis enhance the rate of reaction more effectively than related cationic conventional surfactant tetradecyltrimethylammonium bromide (TTAB). The effect of additives such as salts (inorganic/organic) and organic solvents on the rate was also investigated. The reaction rate was explained in terms of the modified pseudo phase model (considering the association/adsorption of both the reactants on the micellar surface) and changes in micellar morphology occurring at higher [geminis]. The Eyring equation is valid for the reaction over the range of temperatures used. Various thermodynamic parameters and binding constants between reactants with the micelles have been evaluated.

Self-aggregation behaviour of cationic surfactant tetradecyltrimethylammonium bromide and bi-amphiphilic surface active ionic liquid 3-methyl-1-pentylimidazolium dodecylsulfate in aqueous solution

Abstract In this article, we have investigated the micellization behaviour of cationic surfactant tetradecyltrimethylammonium bromide (TTAB) and imidazolium based biamphiphilic surface active ionic liquid (BAIL), 3-methyl-1-pentylimidazolium dodecylsulfate [C5mim][DS] in aqueous solution, by employing various state of art techniques such as conductometry, tensiometry, spectrofluorometry, turbidity, dynamic light scattering (DLS), zeta potential (ζ), 1H NMR, freeze scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The conductometry, and tensiometry measurements have revealed that the micelle formation takes place at lower concentration due to strong synergistic interactions. The aggregation number (Nagg) determined from fluorescence using pyrene as a probe confirms the presence of micelle/vesicles or micelles or vesicles together at different mole fraction ratio of pure components. The various surface parameters have been evaluated by using the tensiometry. Turbidity and DLS measurements have confirmed the formation of micelles as well as vesicles over an exceptionally wide range of concentration (mole fraction = 0.1–0.9). The shape and morphology of the aggregates has been studied by using the FE-SEM and TEM measurements. The 1H NMR measurements shed light on the type of interactions prevail in the two oppositely charged mixed system.

CO2-switchable wormlike micelles based on a switchable ionic liquid and tetradecyl trimethyl ammonium bromide

CO2-responsive wormlike micelles based on ionic liquid 1,1,3,3-tetramethylguanidine-oleic acid (TMG-OA) and cationic surfactant tetradecyl trimethyl ammonium bromide (TTAB) was designed in this work, avoiding the volatileness and flammability of traditional wormlike micelles formed with amines. It provides a new method of preparing CO2-switchable wormlike micelles based on ionic liquid with acidic group. The ionic liquid TMG-OA was prepared by the direct neutralization reaction between TMG and HOA at the molar ratio of 1:1. Due to the excellent stability and switchability demonstrated by thermogravimetry (TGA) and pH, TMG-OA can be treated as nonvolatile surfactant with CO2-responsive acidic group. Then the worm-based viscoelastic fluid is formed by the electrostatic interaction between TTAB and TMG-OA, and the steady and dynamic rheology show that the viscoelastic fluid has CO2-switchable thinning behavior. The switchable behavior is consistent with the reversible transition of microstructure from wormlike micelles to emulsion, which were detected by the dynamic light scattering (DLS) and cryo-transmission electron microscope (Cryo-TEM). The microstructural transition is induced by the reversible conversation between TMG-OA component and HOA component upon CO2 and N2/heat.

Surface tension studies of binary and ternary mixtures of tetradecyltrimethylammonium bromide, ditetradecyldimethylammonium bromide and synperonic PE/F68

The binary mixtures of the nonionic copolymer Synperonic PE/F68 with the cationic surfactants tetradecyltrimethylammonium bromide (TTAB) and/or the double chain ditetradecyldimethylammonium bromide (di-TDAB) were studied. Mixtures of the three surfactants were also studied. Surface tension studies, using the Wilhelmy plate method, were made. Synergy as well as time dependent hindrance effects were found. The minimum equilibrium surface tension value found, was that obtained for single di-TDAB. At concentrations below cmc, clusters were formed (critical aggregation concentration). Synperonic PE/F68, a very hydrophilic compound, minimized the electrostatic repulsion between the positively charged headgroups of the cationic surfactants. The adsorption constants continuously decreased with time. The results were compared with previous ones, using binary mixtures of some double cationic surfactants with Pluronic F68 and/or hydroxypropylmethylcellulose (HPMC). The observed differences were attributed to the higher hydrophilicity of Synperonic PE/F68.

Thermodynamic and spectroscopic studies on cationic surfactant tetradecyltrimethylammonium bromide in aqueous solution of trisubstituted ionic liquid 1, 2-dimethyl-3-octylimidazolium chloride at different temperatures

In this work, the effects on micellar behavior of long chain cationic surfactant tetradecyltrimethylammonium bromide (TTAB) upon the addition of trisubstituted ionic liquid (IL), 1, 2-dimethyl-3-octylimidazolium chloride [odmim][Cl] at temperatures, 298.15–318.15 K has been studied. Different techniques such as conductance, surface tension, fluorescence and 1H NMR have been employed to understand the interactional mechanisms. The values of critical micelle concentration (cmc) and various thermodynamic parameters have been calculated from conductivity measurements. The surface parameters like effectiveness of decrease in surface tension (Πcmc), minimum surface area occupied per surfactant monomer (Amin), maximum surface excess concentration (Γmax), and adsorption efficiency (pC20) have been evaluated by surface tension measurements. Micellar aggregation number (Nagg) has been determined by quenching of pyrene. Further to understand interactions in post micellar region, 1H NMR measurements have been performed. It has been observed that the lipophilicity of interacting ion modified the thermodynamic and aggregation properties of TTAB.

Study of interactions between hyaluronan and cationic surfactants by means of calorimetry, turbidimetry, potentiometry and conductometry

The thermodynamics of the micelle formation of the cationic surfactants tetradecyltrimethylammonium bromide (TTAB) and cetyltrimethylammonium bromide (CTAB) with and without the addition of hyaluronan of two molecular weights was studied in aqueous solution by titration calorimetry. Macroscopic phase separation, which was detected by calorimetry and also by conductometry, occurs when charges on the surfactant and hyaluronan are balanced. In contrast, turbidimetry and potentiometry showed hyaluronan-surfactant interactions at very low surfactant concentrations. The observed differences between systems prepared with CTAB and TTAB indicate that besides the electrostatic interactions, which probably predominate, hydrophobic effects also play a significant role in hyaluronan interactions with cationic surfactants.

Aqueous solution behavior of cationic surfactant modulated by glycol additives: Investigating aggregation and microstructure of tetradecyltrimethylammonium bromide micelles in the presence of propylene glycol, its ethers and esters

The effect of propylene glycol (PG), its monoalkyl ethers and esters on the micellar behavior of a cationic surfactant tetradecyltrimethylammonium bromide (TTAB) in aqueous solution was examined by employing electrical conductivity and small angle neutron scattering (SANS) technique. From conductivity measurements critical micelle concentration (CMC) and degree of counter ion dissociation (α) were evaluated. PG and propylene glycol monomethyl ether (PGMME) delayed micelle formation while propylene glycol monobutyl ether (PGMBE) propylene glycol monomethyl ether acetate (PGMMEA) and propylene glycol diacetate (PGDA) favored the process at studied concentrations. SANS data revealed the effect of all these additives for 100mM TTAB; decrease in micelle size and aggregation number (Nagg) was observed. Results are discussed in terms of effect of additives on water structure and solvent properties and correlated with structure of additives and their octanol-water partition co-efficient values (log Po/w).

Nanoparticle catalysts for proton exchange membrane fuel cells: can surfactant effects be beneficial for electrocatalysis?

Platinum (Pt) nanoparticles were prepared in aqueous dispersion using the non-ionic surfactant nonylphenolethoxylate (NP9) and the cationic surfactant tetradecyltrimethylammonium bromide (TTAB). The surfactants were added to give colloidal stability. Such species are generally considered to block electrochemical active sites and to be undesirable for the oxygen reduction reaction (ORR). However, the procedures used to remove them are likely to cause particle aggregation. The purpose of this work was to investigate the effect of surfactants on Pt ORR performance. The nanoparticles prepared using NP9 showed good oxygen reduction performance when compared with the commercial Pt/C catalyst TKK, without removing the surfactant. In contrast, Pt nanoparticles prepared using the cationic surfactant TTAB showed very poor ORR performance, exemplifying the importance of careful surfactant selection in catalyst synthesis.

Fluorene biodegradation and identification of transformation products by white-rot fungus Armillaria sp. F022

A diverse surfactant, including the nonionic Tween 80 and Brij 30, the anionic sodium dodecyl sulphate, the cationic surfactant Tetradecyltrimethylammonium bromide, and biosurfactant Rhamnolipid were investigated under fluorine-enriched medium by Armilaria sp. F022. The cultures were performed at 25 °C in malt extract medium containing 1 % of surfactant and 5 mg/L of fluorene. The results showed among the tested surfactants, Tween-80 harvested the highest cell density and obtained the maximum specific growth rate. This due Tween-80 provide a suitable carbon source for fungi. Fluorane was also successfully eliminated (>95 %) from the cultures within 30 days in all flasks. During the experiment, laccase production was the highest among other enzymes and Armillaria sp. F022-enriched culture containing Non-ionic Tween 80 showed a significant result for laccase activity (1,945 U/L). The increased enzyme activity was resulted by the increased biodegradation activity as results of the addition of suitable surfactants. The biotransformation of fluorene was accelerated by Tween 80 at the concentration level of 10 mg/L. Fluorene was initially oxidized at C-2,3 positions resulting 9-fluorenone. Through oxidative decarboxylation, 9-fluorenone subjected to meta-cleavage to form salicylic acid. One metabolite detected in the end of experiment, was identified as catechol. Armillaria sp. F022 evidently posses efficient, high effective degrader and potential for further application on the enhanced bioremediation technologies for treating fluorene-contaminated soil.

Dispersion State and Fiber Toughness: Antibacterial Lysozyme‐Single Walled Carbon Nanotubes

AbstractNovel multicomponent fibers that include single‐walled carbon nanotubes (SWNT) and lysozyme (LSZ) are reported. These fibers exhibit antibacterial and mechanical properties suitable for fabrics, clothing and technical textiles in medical environments. The challenging combination of several components in a single fiber material is achieved via fundamental studies on the phase behavior of aqueous LSZ–SWNT dispersions. The addition of molecular cationic surfactants proved to be critical to achieving stable liquid mixtures that can be spun into fibers. In the absence of the cationic surfactant tetradecyl trimethylammonium bromide (TTAB), depletion effects result in large aggregates at relatively low SWNT concentration. However, the addition of TTAB increases the concentration at which demixing occurrs by approximately one order of magnitude. Dry‐spun fibers with significant antibacterial activity and toughness are obtained from LSZ–TTAB–SWNT dispersions combined with a polyvinyl alcohol (PVA) solution. Toughness is strongly affected by the initial dispersion state. The most remarkable fibers are produced from concentrated LSZ–TTAB–SWNT supernatants; they both have four times the toughness of spider silk and 70% of the native LSZ activity.

The Effect of Electrolytes on the Interaction of C. I. Reactive Orange 16-Tetradecyltrimethylammonium Bromide

AbstractThe aim of this study is to investigate the interaction of a cationic surfactant tetradecyltrimethyl ammonium bromide (TTAB) on the electronic absorption spectra of azo dye Reactive Orange 16 (RO16) and to observe the effects of the kind and concentration of electrolytes on these interactions by means of UV-Vis spectroscopy in submicellar and micellar concentration range at a certain temperature (303 K). TTAB affects the electronic absorption spectra of dye solution that is dye-surfactant interaction results into formation of complex and therefore, a decrease in maximum absorption spectra (1.577 at 494 nm). The electrolyte anions cause an increase on the absorbance of TTAB–RO16 ion-pair complex in the following order: Br– > Cl– > SO42– > NO3– > CN– and also for cations; Na+ > K+ > NH4+ > Mg2+. The increase or decrease on absorption spectra of RO16-TTAB solution depends on concentration range of the electrolyte added.

An Investigation of Drug Binding Ability of a Surface Active Ionic Liquid: Micellization, Electrochemical, and Spectroscopic Studies

Keeping in view the use of surfactants in drug delivery, the interactions of surface active ionic liquids, such as 1-tetradecyl-3-methylimidazolium bromide (C(14)mimBr), with drugs, viz., dopamine hydrochloride (DH) and acetylcholine chloride (AC), have been studied, and the results are further compared with that of the structurally similar conventional cationic surfactant tetradecyltrimethylammonium bromide (TTAB). The micellization and interfacial behavior of C(14)mimBr and TTAB, in the presence of DH and AC, has been investigated from conductivity and surface tension measurements. Various micellar and adsorption characteristics for these drug-surfactant systems (DH/AC + C(14)mimBr/TTAB) have been investigated, indicating favorable interactions between them. The more detailed information regarding the nature of interactions between C(14)mimBr/TTAB and DH/AC is obtained from cyclic voltammetry (CV) and (1)H NMR measurements. CV measurements have been employed to evaluate the binding constant (K) and the Gibbs free energy change (ΔG) for these drug-surfactant complexes. These measurements indicate the existence of cation-π as well as π-π interactions between drugs and surfactants. A detailed analysis of chemical shifts of protons of drug molecules (DH and AC) in the presence of C(14)mimBr and TTAB has been done by (1)H NMR. The results obtained from (1)H NMR are in agreement with those of CV measurements. (1)H NMR studies along with the conductivity and surface tension measurements help in predicting the possible location of adsorption of these drug molecules in C(14)mimBr and TTAB micelles.