Dioctadecyldimethylammonium bromide

Dioctadecyldimethylammonium bromide [3700-67-2] M 630.9, m 161-163 . Crystd from acetone then MeOH [Lukac J Am Chem Soc 106 4387 1984]. Also purified by chromatography on alumina by washing with CgHg and eluting with Me2CO, evap and cryst from MeCN [Swain and Kreevoy J Am Chem Soc 77 1126 1955]. 

Monolayers of octadecylmercaptan, dioctadecyldithioethylammonium bromide, and dioctadecyldimethylammonium bromide were used as templates for the growth of gold... 

FIG. 13 Langmuir-Blodgett films of dioctadecyldimethylammonium bromide incorporating 6.0-nm-diameter CdS nanoparticles stabilized by 0.2 mM sodium hexametaphosphate. (a) Absorbance spectra for 2, 3, 4, 5, 6, 7, 8, and 13 layers (bottom to top) the inset shows the linearity of the absorbance at 450 nm versus the number of layers, (b) Fluorescence spectra (excitation wavelength = 400 nm) for 2, 3, 4, 6, 8, 13, and 18 layers (bottom to top) the inset shows the emission intensity at 480 nm versus the number of layers. (Reproduced with permission from Ref. 152. Copyright 1994 American Chemical Society.)... 

Fig. 6 Structure of membrane components (a) dioctadecyldimethylammonium bromide, (b) 1,2-dimyristoyl, s7i-glycero-3-phosphocholine (DMPC), (c) 1,2-dilauroyl, S7i-glycero-3-phospho-choline (DLPC), (d) dicetyl phosphate (DCP)...

The stability of the gel phase and the transitions of coagel and gel phases to liquid crystal in the dioctadecyldimethylammonium bromide-water system were determined by... 

Materials. Dioctadecyldimethylammonium bromide (Eastman Kodak) and chloride (Tokyo Kasei), didodecyIdimethyl-... 

Dioctadecyldimethylammonium bromide [3700-67-2] M 570.5. Crystd from acetone [Lukac JACS 106 4387 1984. ... 

The peak shift due to aggregation is observed not only in LBK films containing azobenzene chromophores, but also for other chromophores with extended Ji-systems, such as viologen polymers. For monolayers of the poly(p-phenylene sulfonate) 9/ dioctadecyldimethylammonium bromide (DODA) complex, the peak shift due to aggregation results in a piezo-chromic effect—that is, upon compression of the monolayer, a significant shift of the poly(p-phenylene sulfate) A band is observed (see Figure 6.9). This photochromic effect has been shown to be based on the improved 7t-Jt interaction upon compression of the monolayer. ... 

Figure 4.35 Large dioctadecyldimethylammonium bromide vesicles may spontaneously rearrange to form tubules in aqueous suspensions. Similar tubules are also observed when lipid 3D crystals swell in water (see Figure 5.1).

Jung, M., German, A.L. and Fischer, H.R. (2001) Polymerisation in lyotropic liquid-crystalline phases of dioctadecyldimethylammonium bromide. Colloid Polym. Sci, 279, 105-113. 

Recently the polymerization of styrene within lamellar and cubic phases of the surfactant DODAB (dioctadecyldimethylammonium bromide) was studied [50]. After polymerization, the polystyrene/water/DODAB system showed the same phase behavior as the binary water/DODAB system, a result suggesting a phase separation during polymerization into a polymer-rich (with M 400,000) and a lyotropic phase. 

Light scattering data reveal that micelles are often spherical at low surfactant concentration. At higher concentrations a transition to rodlike and disclike micelles is observed. Many surfactants depart from this scheme in a manner which is dictated by the molecular KOpeities of the aggregating units. For example, amphiphile molecules with two hydrocarbon chains R and R", such as dioctadecyldimethylammonium bromide DODAB or chloride DODAC as well as the biologically important phosphoglycerides... 

Alkyltrimethylammonium salts (cetyl trimethylammonium bromide, cetyl trimethylammonium chloride), cetylpyridinium chloride, benzalkonium chloride, benzethonium chloride, 5-bromo-5-nitro-l,3-dioxane, dimethyldioctadecylammonium chloride, cetrimonium bromide, dioctadecyldimethylammonium bromide... 

DDAB - didodecrldlmethylauitnonium bromide DODAB - dioctadecyldimethylammonium bromide... 

The hydrocarbon chain melting in surfactant-based systems may give rise to the formation of liquid crystals or molecular or micellar solutions, depending on concentration. The addition of water to surfactant decreases and the enthalpy associated with the transition. This is probably due to a reduction in the cohesion of the polar headgroup network. The effect is especially strong in transitions from solid to solid plus liquid crystals. In pure dioctadecyldimethylammonium bromide (DODAB), the polar layer melts at 86.5°C with a A// of 130 J/g. The transition temperature decreases as water content increases and disappears at about 75% DODAB. At this point, the gel-liquid crystal transition happens at a temperature that is independent of water content [46]. 

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