Of dodecyltrimethylammonium bromide

The relative adsorbability of sulfate against bromide ions of aqueous solution of dodecyltrimethylammonium bromide (0.0150 mole/liter) containing a small amount of sulfate ions (0.0000594 equiv./liter of Na235S04) was summarized in Table II. 

Table II. Relative Adsorbability of 33S042 Against Bromide at the Air-Solution Interface of an Aqueous Solution of Dodecyltrimethylammonium Bromide (0.0150 mole/liter) at 20°C.

S. Ozeki and S. Ikeda, The sphere-rod transition of micelles and the 2-step micellization of dodecyltrimethylammonium bromide in aqueous NaBr solutions, J. Colloid Interface Sci. 87 (1982) 424-435. 

The effects of dodecyltrimethylammonium bromide and chloride, tetradecyltrimethylammonium bromide, CTAB, and NaLS on the dissociation constants of 20a and 20c were investigated by Mukerjee and Banerjee (1964), and the differences between the bulk and the micellar surface pK s of the indicators were interpreted in terms of the electrical potential difference and changes in the pX. Thus, the higher pK at the surface of the cationic micelles as compared to that in the bulk solution can be attributed to a lower effective dielectric constant at the micelle surface. 

Cetrimide consists mainly of trimethyltetradecylammonium bromide (CiyHsgBrN), and may contain smaller amounts of dodecyltrimethylammonium bromide (Ci5H34BrN) and hexadecyltrimethylammonium bromide (Ci9H42BrN). 

Table 6.5 Effect of electrolyte on the micellar properties of dodecyltrimethylammonium bromide CH3(CH2),...

When trace amounts of phosphates were determined in water, they were preconcentrated (as the P-Mo blue) in a column packed with silane-coated glass beads DMF was used as the eluent [116]. The P-Mo blue may also be concentrated on a nitro- or acetylcellulose membrane in the presence of dodecyltrimethylammonium bromide [117]. 

FIGURE 2-14 Adsorption of dodecyltrimethylammonium bromide onto Graphon at 25°C , from pure water , from aqueous 0.1 M KBr. Reprinted with permission from F. G. Greenwood, G. D. Parfitt, N. H. Picton, and D. G. Wharton, Adsorption from Aqueous Solution. Advances in Chemistry Series 79, W. J. Weber, Jr., and E. Matijevic (Eds.), American Chemical Society, Washington, DC, 1968, pp. 135-144. 

The influence of the lyotropic morphology on polymerization rates was studied for a variety of monomers with different polarity and amphiphiUcity [54] in lyotropic phases of dodecyltrimethylammonium bromide in water. The confined geometry of the resulting aggregates has a strong impact on the local monomer concentration and diffusion properties and therefore also on the polymerization kinetics. 

The adsorption of dodecyltrimethylammonium bromide (LNBr) from aqueous solutions on silica and glass slides dewetted by these solutions was measured by using molecules labeled with radioisotopes (C and Br At low LNBr concentrations the counterion, Br , was not adsorbed. It was assumed that the ions were chemisorbed by cation... 

Since then, the dewetting of silica has been extensively studied with solutions of dodecyltrimethylammonium bromide in the presence of HCl and NaOH, as well as the adsorption, 6 g of the dewetting agent at the surface of dewetted vitreous silica. 

For CyD complexes a number of stoichiometric ratios has been observed [2]. The most commonly reported ratios are H G = 1 1 and H G = 2 1. However, other stoichiometries as well as ternary CyD-containing complexes [47] are known. An example of 2 1 stoichiometry is the camphor-a-CyD complex in which the guest molecule is embedded inside a capsule formed by two host molecules [48]. Fenbu-fen (y-oxo-[l,l -biphenyl]-4-butanoic acid) is an interesting example of a compound which shows stoichiometry dependence on the CyD cavity size. It does not form an inclusion complex with a-CyD, but displays H G = 1 1 stoichiometry with f-CyD and H G = 1 2 stoichiometry with y-CyD [49, 50]. Metoprolol is another such compound which forms 1 1 complexes with a-CyD and f-CyD but with y-CyD it forms an H G = 1 2 complex [51]. A similar phenomenon detected using HPLC for a complex with a first-generation dendrimer is presented in Chapter 5 [52]. On the other hand, 1-adamantanecarboxylic acid and f-CyD form a complex with temperature-dependent stoichiometry, H G = 1 1 at 25 °C and H G = 1 2 at 0 °C [28]. For the complexation of dodecyltrimethylammonium bromide with a-CyD two competing associations with stoichiometries of H G = 1 1 and H G = 2 1 have been reported [53]. Use of the method of continuous variations in such situations becomes questionable and information about the complex stoichiometry is revealed directly from the titration measurement described in Section 9.2.3. 

Lokar, W. J. and Ducker, W. A. 2002. Proximal adsorption of dodecyltrimethylammonium bromide to the silica-electrolyte solution interface, Langmuir 18, 3167-3175. 

Water Solubilized by Reverse Aggregates of Dodecyltrimethylammonium Bromide Didodecyidimethylammonium Bromide, and Their Mixtures in Organic Solvents... 

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...

There is a lot of literature so far on the study of hydro-phobic interaction of ethyl(hydroxyethyl)cellulose (EHEC) with various ionic surfactants in water. The techniques used in these studies are of electromotive force of N-tetradecylpyridinium bromide [1], of thermal gelation with sodium dodecylsulfate (SDS) [2], of Fourier transform NMR in the presence of dodecyltrimethylammonium bromide [3], of phase separation diagram with various kinds of anionic and cationic surfactants [4], and so on. These studies have focused on the complex formation between EHEC and these surfactants and on the concomitant phase separation of the polymer solution. 

FIG. 3 Surface tension vs. concentration of the gemini surfactant 12-3-12, 2Br" ( ) and of dodecyltrimethylammonium bromide ( ). (Adapted from data in Refs. 4 and 72.)... 

Fig. 2 Electrophoretic mobility of Na-kaolite in the presence of dodecyltrimethylammonium bromide and NaBr pH = 5, T = 20°C...

M. E Vitha and P. W. Carr,/. Phys. Chem. B, 102,1888 (1998). Study of the Polarity and Hydrogen-Bond Ability of Dodecyltrimethylammonium Bromide Micelles by the Kamlet-Taft Solvatochromic Comparison Method. 

Xu, R, Smart, G., Eleetrophoretie Mobility Study of Dodecyltrimethylammonium Bromide in Aqueous Solution and Adsorption on Microspheres,iuMgmmr, 19%, 12,4125-4133. 

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... 

Herrington, K.L., Kaler, E.W., Miller, D.D., Zasadzinski, J.A., Chiruvolu, S. Phase behavior of aqueous mixtures of dodecyltrimethylammonium bromide (DTAB) and sodium dodecyl sulfate (SDS). J. Phys. Chem. 1993, 97(51), 13792-13802. Khan, M.N., Ismail, E., Yusoff, M.R. Effects of pure non-ionic and mixed non-ionic-cationic surfactants on the rates of hydrolysis of phenyl salicylate and phenyl benzoate in alkaline medium. J. Phys, Org. Chem. 2001,14, 669-676. 

---