DDAB didodecyldimethylammonium

CTAB = cetyltrimethylammonium bromide DDAB = didodecyldimethylammonium bromide DEG = diethylene glycol DOE = dioctyl ether DPE = diphenyl ether DS = dodecyl sulfate EG — ethylene glycol EtOH = ethanol HAD = hexadecylamine HD = 1-hexadecene OD = 1-octadecene HDD = 1,2-hexadecanediol ... 

Reversal of the direction of the EOF using the cationic surfactant didodecyldimethylammonium hydroxide (DDAOH) in reversed polarity mode has also been reported (16). The bromide form of this surfactant (DDAB (didodecyldimethylammonium bromide)) was converted to the hydroxide form to eliminate an undesirable system peak caused by bromide. Using 10 mM phenylphosphonic acid as the probe and a buffer consisting of 200 mM borate, 0.35 mM DDAOH, and 0.03% Trition X-100 at pH 4.0, the separation of 8 alkylphosphonates was achieved in less than 3 min. Eimits of detection were in the 100 xg/L range. 

For most of his vesicle experiments, Menger drops into water a greasy material (a lipid called DDAB, didodecyldimethylammonium bromide). Almost instantaneously, the oily liquid balls up,... 

Vesicles are closed bilayers that can be observed in two forms. At low surfactant concentration, the vesicles are unilamellar and behave like a colloidal suspension of polydisperse particles. At more concentrated surfactant solutions, small multilayered vesicles are formed [134], Multilamellar vesicles (known also as spherulites) have also been observed in the lamellar phases of surfactant-brine (or even pure water-alcohol) systems [218]. The surfactant may be SDS [218,223] or DDAB (didodecyldimethylammonium bromide) [224]. In alcohol-containing systems the bilayer structural transformations are controlled by the alcohol/surfactant ratio [134].Thus, in many SDS-brine (or water)-alcohol systems, a vesicle (L4) phase is located between the micellar phase and the lamellar (L ) phase. At fixed surfactant concentration, the sequence of phases L4 -La-L3 (in water) is obtained by increasing the alcohol content, and the sequence L2 -La-L3 (in oil) is obtained by decreasing the alcohol content [ 134]. 

Arcoleo et a/.[340] used a calorimetric cell to synthesize calcium carbonate from three different microemulsion systems involving one of AOT, DDAB (didodecyldimethylammonium bromide) and C,2E4 as surfactant, n-heptane or isooctane as the oil phase and CaCl2 and Na2C03 or NaHC03 as the precursors in aqueous solutions. The particles were a few nm in size. 

Gold nanoparticles (2.5-7.5 nm diameter) were obtained by Martino and others [402] by reduction of AUCI4 via lithium borohydride in tetrahydrofuran in the reverse micelle system DDAB (didodecyldimethylammonium bromide)/toluene. A purple-colored gold colloid was observable. The particles were encapsulated by silica gels formed in the micellar system by hydrolysis-condensation of TEOS or a prehydrolyzed TEOS, already added in the system. Gelation of silica was achieved by the addition of tetrabutylammonium hydroxide (quicker in case of pre-hydrolyzed TEOS). The particle size was found to be independent of reaction stoichiometry, gel precursor type (TEOS/pre-hydrolyzed TEOS) and the washing step after synthesis. 

The other micellar system used by these authors was DDAB (didodecyldimethylammonium bromide)/toluene. The DDAB solution was used to dissolve C0CI2 hydrate at a concentration of0.005 or 0.01 M. An aqueous solution of NaBH4 (5M) was added in excess under vigorous stirring. Again, a black colloid (more stable than the earlier) was obtained. Hexadecane was added to remove DDAB. The overall particle size of the metallic cobalt (XRD) in this case was -lOnrn with increase in Co concentration from 0.005 to O.OIM, the particle size increased from 7.5 to 13 nm. 

OMC ordered mesoporous carbon, RDE rotating disk electrode, RRDE ring disk electrode, BPG basal plane graphite, PPY Poly(pynole), GO graphene oxide, DDAB didodecyldimethylammonium bromide... 

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. 

Figure 12.25 Phase diagram of didodecyldimethylammonium bromide (DDAB) in water and styrene at 20°C. The phases include an oil-rich isotropic phase L2, lamellar phases, and five distinct cubic strut phases, including the G, D, P, C(P), and an unknown phase C5. Above the cubic phases are regions of two- and three-phase coexistence. (From Strom and Anderson 1992, reprinted with permission from Langmuir 8 691. Copyright 1992, American Chemical Society.)...

Very few rheological data have been reported for ordered cubic phases of surfactant solutions. However, Radiman et al. (1994) have reported dynamic oscillatory data for solutions of didodecyldimethylammonium bromide (DDAB) in deuterated water and octane. Their data for type II cubic P and D phases are shown in Fig. 12-29. They report that the samples... 

Figure 12.29 Frequency-dependence of G ( ), G ( ), and rj (Q) for (a) the P phase and (b) the D phase of a mixture of didodecyldimethylammonium bromide (DDAB) in D2O and octane. (Reprinted with permission from Radiman et al., Langmuir 10 61. Copyright 1994, American Chemical Society.)...

Didodecyldimethylammonium bromide (DDAB) 1508-1509 Diethyl maleate 1466 Diethylentriaminepentaacetate 1123 Diffuse optical tomography (DOT) 1223 DiGeorge syndrome 220 Digitalis 835 Digoxin 58... 

Chen et al. [74] successftilly used fluorescence polarization of an amphiphilic and an oil-soluble probe to monitor the changes of monolayer curvature within the microemulsion phase in didodecyldimethylammonium bromide (DDAB)-alkane-water. 

The SANS method has also been applied to microemulsions formed by using cationic and nonionic surfactants in near-critical propane [47]. A propane microemulsion formed with the cationic surfactant didodecyldimethylammonium bromide (DDAB) exhibits a percolation of the electrical conductivity as the pressure is reduced toward the phase boundary [48]. 

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