Dodecyltrimethylammonium bromide DTAB

Contrary to hydrotropes, micelle-forming surfactants spontaneously self-aggregate cooperatively above the critical micelle concentration (cmc) even in the absence of solubilizate. Typical examples of micelle-forming surfactants include sodium dode-cylsulfate (SDS), dodecyltrimethylammonium bromide (DTAB), cetyltrimethyl-ammonium bromide (CTAB), and heptaoxyethylene dodecyl ether (C12E7) (Scheme 2). 

Our group [124] has used pyrene and pyrene labeled poly(acrylic acid) as a fluorescent probe to investigate the interaction between poly(acrylic acid) (PAA) and dodecyltrimethylammonium bromide (DTAB) in water. We have measured the Is /1 ratio of pyrene as a function of DTAB in the presence of 1 g/L PAA. A sharp decrease in polarity is found well below the CMC of DTAB (1.3 X 10 M, Fig. 17). The onset of this polymer-induced association is referred to as the critical aggregation concentration. The CAC has been measured at various pH and NaCl levels (Fig. 18). It was observed that the... 

Materials. Sodium dodecylsulfate (SDS) and fully deuterated sodium dodecylsulfate (SDS-d ) were obtained from Sigma and Cambridge Isotope Laboratories respectively, and used as received. The cationic surfactants, dodecyltrimethylammonium chloride (DTAC), dodecyltrimethylammonium bromide (DTAB), and didodecyldimethylammonium bromide (DDAB) were purchased from Eastman Kodak, and purified by repeated recrystallization from an ethanol/acetone solvent pair. Even so, a small amount of surface active impurity was observed in surface tension plots for DTAC. The tetradecyldimethylamine oxide (C14AO) was a commercial sample (Ammonyx MO) obtained from Stepan (Control No. 533-30027). This sample is primarily C14AO, but also contains other chain length components. Sodium chloride (NaCl) was obtained from EM Science and used as received. Water was purified by a three stage Bamstead water purification system. 

An increase of the relative amount of protein in the organic phase versus pH would be expected to take place when a cationic surfactant is used. Hatton (2) reported results on solubilization of catalase using a cationic surfactant, dodecyltrimethylammonium bromide (DTAB) in n-octane, with hexanol as cosurfactant. At pH values below pi = 5.3 no solubilization occurred, while there was a significant transfer for pH above pi. 

Some membrane proteins are readily extractable by mild salt solutions. Others, more tenaciously enmeshed, must be solubilized prior to extraction and separation. This requires treatment with detergents such as the anionic sodium dodecyl sulfate (SDS) or the quaternary cationic dodecyltrimethylammonium bromide (DTAB). 

Figure 13 Thermodynamic parameters for the interaction between glucose oxidase and n-dodecyltrimethylammonium bromide (DTAB) as a function of the number of moles of DTAB bound per glucose oxidase molecule (v). AG- ( ), AH (A), and ASp (V) are the Gibbs energy, enthalpy, and entropy per mole of DTAB bound. The symbols and correspond to AG , and TASV corrected for statistical effects. (Data taken from Ref. 88.)...

Dodecyltrimethylammonium bromide (DTAB) cetyltrimethylammonium bromide (CTAB) tetradecyltrimethylammonium chloride (TTAC)... 

Finally, Puig et al. [155] copolymerized styrene with a water-soluble monomer, acrylic acid, in dodecyltrimethylammonium bromide (DTAB) microemulsions initiated by KPS. In this system, the styrene is solubilized within the droplets while acrylic acid is distributed between the aqueous phase and the W/O interphase. This resulted in copolymers with acrylate units randomly distributed among PS blocks. Initiation was assumed to take place at the micelle surface followed by polymerization in the micellar core. 

Kunieda s group reported numerous viscoelastic worm-like micellar systems in the salt-free condition when a lipophilic nonionic surfactant such as short hydrophilic chain poly(oxyethylene) alkyl ether, C EOni, or N-hydroxyethyl-N-methylaUcanolamide, NMEA-n, was added to the dilute micellar solution of hydrophilic cationic (dodecyltrimethylammonium bromide, DTAB and hexade-cyltrimethylammonium bromide, CTAB) [12-14], anionic (sodium dodecyl sulfate, SDS [15, 16], sodium dodecyl trioxyethylene sulfate, SDES [17], and Gemini-type [18]) or nonionic (sucrose alkanoates, C SE [9, 19], polyoxyethylene cholesteryl ethers, ChEO [10, 20], polyoxyethylene phytosterol, PhyEO [11, 21] and polyoxyethylene sorbitan monooleate, Tween-80 [22]) surfactants. The mechanism of formation of these worm-Hke stmctures and the resulting rheological behavior of micellar solutions is discussed in this section based in some actual published and unpublished results, but conclusions can qualitatively be extended to aU the systems studied by Kunieda s group. 

Figure 20.11. Addition of a surfactant to a solution of a hydrophobically modified polyelectrolyte (in this case hydrophobically modified polyacrylate) gives very different viscosity effects for different types of surfactants. The effect is much larger for an oppositely charged surfactant, dodecyltrimethylammonium bromide (DTAB), than it is for a nonionic (C12E5) or a similarly charged one, sodium dodecyl sulfate (SDS). (Redrawn from B. Magny, I. Iliopoulos, R. Audebert, L. Piculell and B. Lindman, Progr. Colloid. Polym. ScL, 89 (1992) 118)...

The feasibility of using MLC to separate organotin compounds with a C18 reversed-phase column was investigated [14]. Among the three types of surfactants (anionic SDS, cationic dodecyltrimethylammonium bromide, DTAB and nonionic Brij 35), only SDS was found to resolve these compounds. The use of positively charged or nonionic micelle mobile phase resulted in a lack of interaction with the organotin cations. Therefore, these mobile phases caused the compounds either to come off with the void volume or to become irreversibly adsorbed on the stationary phase. 

PILs contairring long alkyl chairrs have been used as surfactants in a solvent, such as a series of 1-alkylimidazo-lium nitrates or chlorides (with alkyl chairrs of n = 14, 16, or 18), which formed liquid crysMs in water, acidic water, or tetrahydrofuran (THE). The CMCs of hexyl-, heptyl-, and octylammonium nitrates in water were fourrd to decrease with increasing alkyl chain length and were larger than the CMCs of the anionic surfactant sodium dodecyl sulfate (SDS) or the cationic surfactant dodecyltrimethylammonium bromide (DTAB). 3o... 

Emulsion droplet charge can be an important factor in l id oxidation rates in oil-in-water emulsions, as well as in other lipid dispersions. When com oil-in-water emulsions are prepared with anionic (sodium dodecyl sulfate SDS), cationic (dodecyltrimethylammonium bromide DTAB) or nomonic (Brij 35) surfactants, iron-promoted lipid oxidation is in tiie order of SDS>Brij 35>DTAB (13). The prooxidant activity of iron in the SDS-stabilized emulsions increased at low pH (3.0) where iron solubility increases. The high... 

More extensive are studies involving reaction of a well-defined Ru catalyst (typically 2) with the unprotected monomers in water or methanol. As 2 is insoluble in these media, it is usually predissolved in a chlorocarbon solvent. For reactions in water, intimate contact between monomer and catalyst is then promoted by use of methanol as co-solvent, or by use of an emulsifying agent such as dodecyltrimethylammonium bromide (DTAB). The impact of die conditions chosen on polymer chain lengfli and polydispersity is discussed below. A note concerning characterization is warranted, however. Analysis of the molecular weights of the resulting water-soluble ROMP polymers is... 

Figure 5.13 Conductance of dodecyltrimethylammonium bromide (DTAB) as a function of total monomer concentration (cmc = 0.016 mol/L). ( ) experimental data (personnal experiments). 1 Ideal case, 2 Limiting law (Onsager), 3 Theoretical results ( MSA). Parameters = 4.5 10 ° (obtained through...

Whereas an ethoxylated alcohol with dodecyl tails (e.g. C12E5) forms middle-phase microemulsions, ionic surfactants with dodecyl tails, such as sodium dodecyl sulfate (SDS) or dodecyltrimethylammonium bromide (DTAB), are too hydrophilic for formation of middle-phase microemulsions. Simply increasing the length of the hydrocarbon tail to compensate for the high hydrophilicity of the ionic head-groups favours the formation of viscous liquid crystal line phases rather than fluid microemulsion phases (36, 37). However, increasing the hydrophobicity by adding double tails to the surfactant, as for example with didodecyldimethylam-monium bromide surfactant (DDAB), suppresses some of the tendency to form liquid crystals, and allows for formation of oil-rich microemulsions (38). However, this surfactant is too hydrophobic, and is far from the... 

Without addition of salt, Aerosol OT forms a much-studied region of oil-rich microemulsions (41). However, the even more hydrophilic single-tailed surfactants such as sodium dodecyl sulfate (SDS) and dodecyltrimethylammonium bromide (DTAB) are so far from the optimal hydrophilic-lipophilic balance that addition of salt alone is not enough for the formation... 

Sodium dodecylsulfate (NaDDS) was supplied by BDH, specially pure grade. Dodecylammonium chloride (DAQ and dodecyltrimethylammonium bromide (DTAB) were supplied by Eastman Kodak. The alcohols 1-hexanol (QOH), 1-heptanol (C7OH), and 1-octanol (CjOH) were supplied by Fluka at their best quality. All compounds were used without further purification. Water was distilled twice immediately before use. All solutions were made by weight. 

Eriochrome cyanine R (also known as mordant blue 3) + iVAl-dodecyltrimethylammonium bromide (DTAB)... 

Dodecyltrimethylammonium bromide (DTAB or DTA Br") was obtained from Aldrich Chemie and used without further purification. 

SEM images of fibres electrospun from 2% PAN/DMF solution (a) the solution does not contain any additives (b) the solution contains 0.1% (w/v) dodecyltrimethylammonium bromide (DTAB). 

We exemplify here the precipitation behavior of DNA with the addition of dodecyltrimethylammonium bromide (DTAB) [36]. This is a surfactant with a relatively short alkyl chain, which allows for a rather fast equilibration of the samples also this surfactant forms a micellar solution up to relatively high surfactant concentrations [37]. Figure 10.5a shows a schematic representation of the ternary phase diagram. As expected, the aqueous mixture of DNA and cationic surfactant phase separates associatively into one dilute phase and one phase concentrated in both polyelectrolyte and surfactant, a precipitate. The electrostatic interactions... 

Fig. 6.37 Solubilization of Orange OT by solutions of 12,12,12-trifluorodode-cyltrimethylammonium bromide (TDTAB) and dodecyltrimethylammonium bromide (DTAB) in 0.5M NaBr. (From Ref. 194. Reproduced by permission of Academic Press.)...

Kriegel et al. [165] again found that the addition of PEO (25% of polymer content) facilitated fiber formation from chitosan. They included in the blend fibers different surfactants, i.e. sodium dodecyl sulfate (SDS), dodecyltrimethylammonium bromide (DTAB) and polyoxyethylene glycol (23) lauryl ether (Brij 35). The surfactants can be retained in the nanofibers either in the form of micelles or monomers. Furthermore, the addition of... 

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