Dodecyltriethylammonium Bromide Research Articles

Influence of series of long-chain cationic surfactants on the quality characteristics of nano silica induced zinc phosphated mild steel

Abstract Mild steel panels were zinc phosphated employing environmentally safe nano silica as an accelerator and a series of four cationic surfactants as additives. The four cationic surfactants chosen were decyltriethyl ammonium bromide (C10TEAB), dodecyltriethyl ammonium bromide (C12TEAB), hexadecyltriethyl ammonium bromide (C16TEAB), and octadecyltriethyl ammonium bromide (C18TEAB). The length of the alkyl chain of the surfactant compounds influenced the quality of the coatings. The corrosion resistance of the coated panels was assessed using a salt spray test. The hydrophobicity of the coatings increased as the hydrocarbon chain length of the surfactants extended from C10 to C18. Porosity, adhesion, and roughness tests were used to examine the surface properties of the coated panels. The coating weight and thickness of the resultant coatings on the base metal were used to quantify coating quality. The results of the tests revealed that the presence of C16TEAB additive outperformed all other components in terms of coating efficiency, coating thickness, and corrosion inhibition performance. The optimal quantity of C18TEAB deposited had a maximum coating weight of 0.0430 g/mm2 that enhanced durability, appearance, and barrier qualities.

Cationic Single-Chained Surfactants with a Functional Group at the End of the Hydrophobic Tail DNA Compacting Efficiency.

The interaction between calf-thymus DNA, ctDNA, and various single-chained surfactants with different functional groups at the end of hydrophobic tail was studied with the goal of investigating the influence of the functional group nature on surfactant DNA compacting efficiency. The surfactants investigated were dodecyltriethylammonium bromide (DTEABr), triethyl(1-phenoxydodecyl)ammonium bromide (12PhBr), triethyl(2-naphthoxydodecyl)ammonium bromide (12NBr) and 11-(isonicotinoyloxy)-N,N,N-triethyl-1-undecanaminium bromide (11PyBr). Results made evident that the surfactants’ tendencies to self-aggregation is the key factor determining their efficiency to compact the nucleic acid. Subsequently, DOPE/12NBr/pEGFP-C1 lipoplexes, with different cationic surfactant molar fractions (α) and mass ratios (L/D), were prepared and characterized. DOPE is a zwitterionic phospholipid 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine, and the plasmid pEGFP-C1 carries a GFP coding sequence with the necessary regulatory elements for constitutive expression of the gene in human cells. 12NBr was chosen because it was the most efficient DNA compacting agent among the surfactants investigated. Finally, the cytotoxicity and transfection efficiency (TE) of DOPE/12NBr/pDNA lipoplexes, with different compositions, were investigated.

Antibacterial, Antifungal and Ecotoxic Effects of Ammonium and Imidazolium Ionic Liquids Synthesized in Microwaves.

Ionic liquids are increasingly used for their superior properties. Four water-immiscible ionic liquids (butyltriethylammonium bis(trifluoromethylsulfonyl)imide, octyltriethylammonium bis(trifluoromethylsulfonyl)imide, dodecyltriethylammonium bis(trifluoromethylsulfonyl)imide, butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) and their water miscible precursors (bromides) were synthesized in a microwave reactor and by conventional heating. The best conditions for microwave-assisted synthesis concerning the yield and the purity of the product are proposed. The heating in the microwave reactor significantly shortened the reaction time. Biocide and ecotoxic effects of synthesized ionic liquids and their precursors were investigated. All tested compounds had at least a little effect on the growth or living of microorganisms (bacteria or mold). The precursor dodecyltriethylammonium bromide was found to be the strongest biocide, but posed a risk to the aquatic environment due to its relatively high EC50 value in the test with Vibrio fischeri. We assumed that apart from the alkyl chain length, the solubility in water, duration of action, or type of anion can influence the final biocide and ecotoxic effect.

Surfactant effect on controllable phase transformation and UV-shielding performance of titanium dioxide

The crystalline structure, size and morphology of TiO2 have crucial influence on its physicochemical performance. The crystal growth process includes crystal transformation and morphology evolution, which is closely related to the solution environment. In this work, rutile TiO2 was synthesized via surfactant-assisted method by using titanium sulfate as titanium source. Factor associated with crystalline structure of TiO2 were investigated including surfactant type and concentration. Results showed that when the concentration of cetyltriethylammonium bromide (CTMAB) was greater than or equal to 3 mmol/L, or the concentration of dodecyltriethylammonium bromide (1231) was greater than or equal to 4 mmol/L, surfactants promoted transformation from anatase to rutile titania. The UV-shielding performance of the surfactant-aided titania increased, and the band gap width decreased by 0.2–0.3 eV. More importantly, we found that the cationic surfactant played a decisive role in anatase-rutile transformation of titania. The microspherical cationic surfactant micelles were chelated by electrostatic adsorption and [TiO6] octahedron, and the [TiO6] octahedron tended to grow to the opposite side, which was formed to form rutile titania.

Host-guest interactions between cyclodextrins and surfactants with functional groups at the end of the hydrophobic tail

The aim of this work was to investigate the influence of the incorporation of substituents at the end of the hydrophobic tail on the binding of cationic surfactants to α-, β-, and γ-cyclodextrins. The equilibrium binding constants of the 1:1 inclusion complexes formed follow the trend K1(α-CD)>K1(β-CD)≫K1(γ-CD), which can be explained by considering the influence of the CD cavity volume on the host-guest interactions. From the comparison of the K1 values obtained for dodecyltriethylammonium bromide, DTEAB, to those estimated for the surfactants with the substituents, it was found that the incorporation of a phenoxy group at the end of the hydrocarbon tail does not affect K1, and the inclusion of a naphthoxy group has some influence on the association process, slightly diminishing K1. This makes evident the importance of the contribution of hydrophobic interactions to the binding, the length of the hydrophobic chain being the key factor determining K1. However, the presence of the aromatic rings does influence the location of the host and the guest in the inclusion complexes. The observed NOE interactions between the aromatic protons and the CD protons indicate that the aromatic rings are partially inserted within the host cavity, with the cyclodextrin remaining close to the aromatic rings, which could be partially intercalated in the host cavity. To the authors’ knowledge this is the first study on the association of cyclodextrins with monomeric surfactants incorporating substituents at the end of the hydrophobic tail.

One platform solid multicolour emission of terthiophene compounds controlled by mixed self-assembly.

Via the mixed self-assembling procedure, solid multicolour emission materials based on an amphiphilic terthiophene compound are obtained from a unimolecular platform. Upon controlling the concentration of the cationic surfactant dodecyltriethyl ammonium bromide (DEAB) in the precipitate-monomer equilibrium system of the terthiophene compound TTC4L, mixed self-assembly of TTC4L-DEAB results in diverse structures (including plates, spheres, and needles) with different emission colours. The multicolour emissions are triggered by the different distances between the terthiophene groups in these mixed self-assemblies. Each distance corresponds to a specific molecular state of terthiophene groups, so that emissions corresponding to the monomers, excimers, and aggregates are obtained. Upon variation of the ratio of DEAB and TTC4L, the relative fraction of emissions corresponding to the monomers, excimers, and aggregates of TTC4L changes. This approach may act as a simple method to control the stacking mode of the oligothiophene group which is anticipated to realize unimolecular-platform multicolour emissions.

Polymeric Suppression of Dopant‐Enhanced Surfactant Supramicellar Assemblies

Certain hydrophobic dopants in surfactant solutions cause massive “supramicellar assemblies” (SAs) to form near the critical micelle concentration (CMC), characterized by a light‐scattering peak (LSP). The SAs are large, dynamic, metastable nanostructures composed of surfactant/dopant. Here, a water‐soluble polymer, poly(vinylpyrollidone) (PVP) suppresses SA formation in sodium dodecyl sulfate (SDS) solutions doped with dodecanol, but increases solution instability. Binding of SDS to PVP is stronger than micellization in the LSP regime, reflected in a decreased SA population and a dramatic reduction and inversion of Rayleigh scattering IR as [PVP] increases, since SAs are much more massive than PVP/SDS association structures. Above the LSP regime, SAs no longer exist and thus IR must re‐establish its order, increasing with increasing [PVP]. This causes a cross‐over in IR vs [SDS] with an “iso‐scattering point,” where IR converges at a specific [SDS]. Weak LSP suppression is found using dodecyl tri­ethyl ammonium bromide (DTAB). Poly(ethylene oxide) (PEO)’s effect is small compared with PVP. image

Vesicle formation between single-chained cationic surfactant and plasmid DNA and its application in cell transfection

In the present study, we found that plasmid DNA could induce single-chained cationic surfactants cetyltrimethylammonium bromide (CTAB), dodecyltrimethylammonium bromide (DTAB), and dodecyltriethyl ammonium bromide (DEAB) to form vesicles once its concentration reached a critical value. Moreover, the gene for follicle-stimulating hormone was delivered into cells with these single-chained cationic surfactant/DNA vesicles and the transfection efficiency was comparable to that with lipofectamine™ 2000, a famous and widely used commercial transfection reagent, and also to that using electroporation method, although it was generally thought conventional single-chained cationic surfactant was not suitable for gene transfer. The conventional single-chained cationic surfactant is very cheap and stable and the vesicles are very easy to be prepared. Thereby, this study may suggest that the vesicles formed between plasmid DNA and surfactant should be prospective to transfer DNA.

Synthesis of cubic Pm3n supermicroporous silicas and aluminosilicates under alkaline condition

Ordered cubic Pm3n supermicroporous silica and aluminosilicate materials were synthesized using dodecyltriethylammonium bromide as template and sodium silicate as silicon source under alkaline condition. The cubic Pm3n structures were confirmed by XRD patterns and TEM images. Ordered supermicroporous silica could be obtained facilely at room temperature. As the incorporation of Al resulted in a decrease in the cubic ordering, ordered supermicroporous aluminosilicates should be synthesized at lower temperature. A series of aluminosilicates was prepared and the SiO2/Al2O3 molar ratio in products could be achieved as low as 32 with the cubic Pm3n structure well-preserved. Nitrogen sorption data further proved the supermicropore size of the materials.

Highly ordered supermicroporous aluminosilicates with cubic Pm3n symmetry fabricated in weakly acidic solution

Highly ordered supermicroporous aluminosilicates with cubic Pm3n symmetry were prepared for the first time in weakly acidic solutions of succinic acid and malonic acid using dodecyltriethylammonium bromide as a template. The polycarboxylic acids acted as auxiliaries for fabricating the cubic Pm3n structure as well as weak acids. Thermally stable aluminosilicates with a high utilization ratio of Al could be obtained in the presence of succinic acid by either facilely adding aluminum source into the initial synthesis gel or by grinding the as-made silica-surfactant composite with aluminum nitrate. In contrast, thermally stable aluminosilicates could only be prepared via a post-synthesis approach in the presence of malonic acid, probably because of the powerful coordination tendency between malonic acid and Al cations. The thermal stability of the aluminosilicates was enhanced because of the incorporation of Al into the framework or grafting of Al onto the pore walls. Aluminosilicates prepared via the post-synthesis approach preserved the cubic Pm3n structure better than the directly-synthesized ones. In spite of the kind of polycarboxylic acids or the preparation methods, Al was predominantly tetrahedrally coordinated. The aluminosilicates showed a high specific area and pore volume, especially for the post-synthesized ones. The pore size was in the supermicroporous range evidenced by N2 physisorption, though that of the aluminosilicates prepared via the post-synthesis approach was larger. TEM images verified the Pm3n symmetry of the materials herein. The cubic Pm3n aluminosilicates prepared in our research exhibited equal reactivity but a much pronounced deactivation resistance property in the acetalization of cyclohexanone with pentaerythritol.

Plasmid DNA induces dodecyl triethyl ammonium bromide to aggregate into vesicle

Abstract Single-chained cationic surfactant dodecyl triethyl ammonium bromide and plasmid DNA together can form vesicles once the concentration of plasmid DNA reaches a critical value (Ccvc). Bigger the size of plasmid DNA, higher the value of Ccvc.

One-Pot Synthesis of Dendritic Gold Nanostructures in Aqueous Solutions of Quaternary Ammonium Cationic Surfactants: Effects of the Head Group and Hydrocarbon Chain Length

Hierarchical, three-fold symmetrical dendritic gold was prepared in an aqueous solution of the quaternary ammonium cationic surfactant dodecyltrimethylammonium bromide (DTAB). Similar surfactants with different head groups and hydrocarbon chain lengths were also used for comparison. Two-fold and one-fold symmetrical dendritic gold nanostructures were obtained in N-dodecyl-N-methylpyrrolidinium bromide (C(12)-MPB) and dodecyltriethylammonium bromide (DTEAB) aqueous solutions, respectively. Longer hydrocarbon chain lengths were unfavorable for the formation of dendritic nanostructures. The interaction energies between the individual surfactants and Au (111) plane were calculated using molecular dynamics simulations. Based on a series of contrast experiments and molecular dynamics simulations, the possible growth mechanism and fabrication process of the dendritic structures were proposed. The DTAB-capped, three-fold gold dendrites exhibited good surface-enhanced Raman scattering (SERS) sensitivity toward rhodamine 6G (R6G), indicating their potential for use in SERS-based detections and analysis. This work provides a simple and effective strategy for fabricating dendritic gold nanostructures in aqueous solutions.

Kinetics of thermo-induced micelle-to-vesicle transitions in a catanionic surfactant system investigated by stopped-flow temperature jump

The kinetics of thermo-induced micelle-to-vesicle transitions in a catanionic surfactant system consisting of sodium dodecyl sulfate (SDS) and dodecyltriethylammonium bromide (DEAB) were investigated by the stopped-flow temperature jump technique, which can achieve T-jumps within ∼2-3 ms. SDS/DEAB aqueous mixtures ([SDS]/[DEAB] = 2/1, 10 mM) undergo microstructural transitions from cylindrical micelles to vesicles when heated above 33 °C. Upon T-jumps from 20 °C to final temperatures in the range of 25-31 °C, relaxation processes associated with negative amplitudes can be ascribed to the dilution-induced structural rearrangement of cylindrical micelles and to the dissolution of non-equilibrium mixed aggregates. In the final temperature range of 33-43 °C the obtained dynamic traces can be fitted by single exponential functions, revealing one relaxation time (τ) in the range of 82-440 s, which decreases with increasing temperature. This may be ascribed to the transformation of floppy bilayer structures into precursor vesicles followed by further growth into final equilibrium vesicles via the exchange and insertion/expulsion of surfactant monomers. In the final temperature range of 45-55 °C, vesicles are predominant. Here T-jump relaxations revealed a distinctly different kinetic behavior. All dynamic traces can only be fitted with double exponential functions, yielding two relaxation times (τ(1) and τ(2)), exhibiting a considerable decrease with increasing final temperatures. The fast process (τ(1)∼ 5.2-28.5 s) should be assigned to the formation of non-equilibrium precursor vesicles, and the slow process (τ(2)∼ 188-694 s) should be ascribed to their further growth into final equilibrium vesicles via the fusion/fission of precursor vesicles. In contrast, the reverse vesicle-to-micelle transition process induced by a negative T-jump from elevated temperatures to 20 °C occurs quite fast and almost completes within the stopped-flow dead time (∼2-3 ms).

Microstructures and rheological dynamics of viscoelastic solutions in a catanionic surfactant system

Viscoelastic solutions formed in a catanionic surfactant system of dodecyltriethylammonium bromide (DTEAB)/sodium dodecylsulfate (SDS) at the molar ratio of 27/73 were systematically studied using a combination of rheology and dynamic light scattering (DLS). Wormlike micelles began to form above the total surfactant concentration ( C total) of 120 mM by the growth of small cylindrical micelles. Subsequently the system was found to exhibit linear viscoelasticity with characteristic of a Maxwell fluid in the intermediate concentration range of 170–210 mM, which arose from a 3D entangled network of wormlike micelles. At higher surfactant concentrations, a transition from linear micelles to branched structures probably took place. Finally and significantly, the effect of the surfactant headgroup on the rheological property of catanionic surfactant mixtures was discussed.

Micelle‐to‐vesicle transition induced by oligonucleotide in SDS/DEAB mixed system with a net negative charge

AbstractSodium dodecyl sulfate (SDS)/dodecyl triethyl ammonium bromide (DEAB) mixed micelles (with SDS in excess) can transform to vesicles only when the temperature is higher than a critical value. In this study, we report for the first time that oligonucleotide can decrease the critical temperature to a much lower value and, hence, induce micelle‐to‐vesicle transition. The facilitation efficiency of oligonucleotide on vesicle formation is closely dependent on its size and base composition. Moreover, the SDS/DEAB/oligonucleotide vesicles are negatively charged and the hydrophobic interaction between oligonucleotide and SDS/DEAB mixed micelles is the driving force. As, so far, the report about the facilitation effect of oligonucleotide and DNA on vesicle formation is very limited, this study may provide some helpful information for the application of DNA/amphiphile system. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7491–7504, 2008

Salt Effect on Microstructures in Cationic Gemini Surfactant Solutions as Studied by Dynamic Light Scattering

A cationic gemini surfactant, dodecanediyl-1,12-bis(dodecyldiethylammonium bromide) (C12C12C12(Et)), in aqueous solutions with varying NaBr concentration was studied by dynamic light scattering (DLS). As a comparison, its single-chained counterpart, dodecyl triethylammonium bromide (DTEAB), was also investigated under the same conditions. Similar to the case of a polyelectrolyte, C12C12C12(Et) underwent a typical "ordinary-to-extraordinary (o-e) transition" with decreasing salt concentration to zero. At higher salt concentration, a single relaxation mode, corresponding to the diffusion of regular micelles, was observed. While in the "extraordinary regime", DLS detected two characteristic relaxation modes with the values of the diffusion coefficient being different by at least 2 orders. The fast mode was consistent with the polyion-small ion coupled-mode theories, as well as the direct polyion-polyion repulsion interactions. Because the slow mode disappeared at elevated salt concentrations and generated negligible scattered intensity, we attributed it to multimacroion domains.

Vesicle aggregation in aqueous mixtures of negatively charged polyelectrolyte and conventional cationic surfactant

Vesicle aggregation induced by different environmental factors, including the addition of divalent metal ions, decrease of pH, and increase of temperature—was investigated through turbidity measurement, fluorescence measurement, and transmission electron microscope observation in aqueous solutions of hydrolyzed styrene–maleic anhydride copolymer (HSMA) mixed with dodecyltriethylammonium bromide (C 12Et 3). The vesicle aggregation can be explained by the dehydration of the vesicle surface through cations addition or temperature increase based on an analysis of the interaction between vesicles. Moreover, the steric repulsion was introduced to the system and the control of vesicle aggregation was achieved.

Experimental study on the special shear thinning process of a kind of non-Newtonian fluid

To study the effect of long chain molecule and surface active agent on non-Newtonian fluid properties, rheological experiments on two different fluids have been done. The first group of the fluid is the hydroxyethyl cellulose water solution, and the second is the water solution containing the mixture of dodecyltriethyl ammonium bromide and lauryl sodium sulfate. With the increasing shear rate, shear thinning phenomenon appears in the first group of solution, and a special shear thickening-shear thinning phenomenon appears in the second group. It is considered that the special rheological phenomenon is caused by the difference between the aggregating and the departing speed of the colloidal particles formed in the fluid. The difference between the two speeds relates with the shear rate. The experiment results indicate that the rheological properties can be designed by choosing proper additives at a certain shear rate, and such a fluid with special viscosity variation should be included in the classification of the non-Newtonian fluid.

Multivalent Metal Ion Induced Vesicle Aggregation in Aqueous Polyelectrolyte-surfactant System

Abstract The vesicle aggregation induced by multivalent metal ions in the mixed system of polyelectrolyte (hydrolyzed random copolymer of maleic anhydride-styrene, SMA)-surfactant (dodecyltriethylammonium bromide, DEAB) was investigated by transmission electron microscopy (TEM) observation and turbidity measurement. It was found that a small amount of Ca 2+ (in the magnitude of 10 −4 mol·L −1) could induce vesicle aggregation. Addition of EDTA can dissociate the vesicle aggregation. Further investigation suggested that the vesicle aggregation followed the salt-linkage mechanism.

Phase behavior and protein partitioning in aqueous two-phase systems of cationic–anionic surfactant mixtures

Cationic–anionic surfactant mixtures can form aqueous two-phase systems. Such aqueous surfactant two-phase systems (ASTP systems) can be used for separation and purification of biomaterials. In this work we investigated the phase behavior and the partitioning of BSA and lysozyme in the ASTP system formed by mixtures of dodecyltriethylammonium bromide and sodium dodecylsulfate (SDS). The pseudo ternary phase diagram of these mixtures at low total surfactant concentrations contains two narrow two-phase regions, which represent two kinds of different ASTP systems formed when cationic and anionic surfactants are in excess, respectively (called ASTP-C and ASTP-A). The phase separation is associative, one phase is surfactant-rich, and the other phase is surfactant-depleted. Mechanisms behind the phase behavior are discussed. The phase behavior, especially phase separation time and phase volume ratio, is strongly influenced by total concentration and molar ratio of mixed surfactants. The effect of molar ratio is strong, which enables one to get desired phase systems also at very low total concentration by tuning the molar ratio of the surfactants. It was shown that the marked differences of surfactant concentration between the phases makes proteins distribute with different partitioning coefficients. The charges on the micellar surface, which can be adjusted by tuning the molar ratio of cationic surfactants to anionic surfactants, enhance the selectivity of protein partitioning by electrostatic effects. At pH 7.1, in the ASTP-C systems, negatively charged BSA is concentrated in the surfactant-rich phase and positively charged lysozyme in the surfactant-depleted phase, while in ASTP-A systems, a totally opposite partitioning was observed. It was shown that lysozyme could retain activity in ASTP systems.