- Three-Component Ionic Microemulsions
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Necessary design features of microemulsions formed from cationic surfactant without any requirement for cosurfactant are illustrated by a study of microemulsions formed from didodecyldimethylammonium bromide in various oils.Ease of purification, preparation, and manipulation give this and related systems a considerable advantage over conventional systems in enhancing our understanding of microemulsions and emulsion behavior.
- Angel, Lindsay R.,Evans, D. Fennell,Ninham, B. W.
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- Meaning and Structure of Amphiphilic Phases: Inferences from Video-Enhanced Microscopy and Cryotransmission Electron Microscopy
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This paper attempts to come to grips with a major issue confronting association colloid science.It does so by illustrating some surprising features of aggregates of simple amphiphiles as revealed by two powerful complementary tools, video-enhanced microscopy (VEM) and cryotransmission electron microscopy (cryo-TEM), both of which allow direct visualization.The natures of these aggregates challenge existing theories and show up limitations of some other noninvasive, though indirect, techniques.The problem of the meaning of amphiphilic phases and their microstructure is discussed and the necessity for a different descriptive language emphasized.
- Miller, D. D.,Bellare, J. R.,Evans, D. F.,Talmon, Y.,Ninham, B. W.
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- Synthesis of some acyclic quaternary ammonium compounds. Alkylation of secondary and tertiary amines in a two-phase system
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A series of acyclic symmetrical and asymmetrical quaternary ammonium chlorides of the general formula R1R2R3N+AR4Cl- (R1 = Me, Bu; R2 = n-C12H25, PhCH2, C n H2n+1(OCH2CH2) m, n = 9 and 12, m = 1 and 2; R3 = n-C12H25, PhCH2, HOCH2CH2,-OOCCH2; R4 = n-C12H25, PhCH2; A = (CH2CH2O)1,2, CH2C(O)O) was synthesized by the alkylation of tertiary amines in a two-phase system containing water. A convenient method for the synthesis of the initial symmetrical and asymmetrical tertiary amines of the general formula MeNR1R2 (R1 = Me, Bu; R2 = n-C12H25, PhCH2, CnH2n+1(OCH2CH2) m, n = 9 and 12, m = 1 and 2) in an organic phase-aqueous phase heterogeneous system, which allows the use of aqueous solutions of alkali and amines, was developed. The improved method for the preparation of intermediate ethylene glycol and diethylene glycol monoethers is monoalkylation of glycols in dioxane using solid KOH in a two-phase system.
- Kharlamov,Artyushin,Bondarenko
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p. 2445 - 2454
(2015/08/03)
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- Luminescent logic function of a surfactant-encapsulated polyoxometalate complex
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We have fabricated a novel organic/inorganic hybrid material consisting of multifunctional surfactant-encapsulated polyoxometalloeuropate which functions as a luminescent logic gate with dual output operated by light and metal ion as inputs. The Royal Society of Chemistry 2006.
- Zhang, Hui,Lin, Xiankun,Yan, Yi,Wu, Lixin
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p. 4575 - 4577
(2007/10/03)
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- METHOD FOR THE SYNTHESIS OF QUATERNARY AMMONIUM COMPOUNDS AND COMPOSITIONS THEREOF
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A novel manufacturing process is described for producing quaternary ammonium compounds having a selected anion, which may be useful in wood preservative formulations. The process involves reacting a trialkylamine with an alkyl bromide to form a quaternary tetraalkylammonium bromide salt, converting the quaternary tetraalkylammonium bromide salt to a quaternary tetraalkylammonium hydroxide salt by using an ion exchange resin, and converting the quaternary tetraalkylammonium hydroxide salt to the quaternary tetraalkylammonium salt of the selected anion.
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Page/Page column 49-50; 56-57
(2008/06/13)
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- Properties of Dilute Aqueous Solutions of Double-Chain Surfactants, Alkyldodecyldimethylammonium Bromides with a Change in the Length of the Alkyl Chains
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A series of cationic surfactants, dialkyldimethylammonium bromides with dodecyl as the primary alkyl chain and with methyl, ethyl, propyl, butyl, hexyl, octyl, and decyl as the second alkyl chain, as well as those with symmetric alkyl chains, dioctyl, didecyl and didodecyl ones, were synthesized, and their properties were investigated through measurements of the conductivity and air-liquid surface tension for their aqueous solutions to determine their critical micelle concentrations (cmc) and surface adsorption parameters in the formulation according to a two-dimensional lattice model in the form of the Frumkin equation. The change in cmc revealed that the free energy to transfer from water to the micelle per methylene unit is significantly small for asymmetric double-chain surfactants with a shorter second alkyl chain, and it approaches as elongating the second alkyl to those for the single-chain and symmetric double-chain surfactants. The free energy to transfer to an air-solution interface decreased approximately linearly with the total length of the hydrocarbon chains for all of the species examined. The lattice area for a symmetric double-chain surfactant molecule decreased with the length of its hydrocarbons. In a series of asymmetric ones, it showed a maximum for that with hexyl in its second alkyl.
- Hiramatsu, Koichi,Kameyama, Keiichi,Ishiguro, Ryo,Mori, Masaki,Hayase, Hisao
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p. 1903 - 1910
(2007/10/03)
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- Method of encapsulation and microcapsules produced thereby
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Microcapsules are prepared by dispersing or dissolving an active component or components in a solid matrix-forming material that has been thermally softened to form an encapsulation composition. The encapsulation composition is injected as an intact stream into a quenching liquid to provide solid microcapsules.
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- The Effects of Single- and Twin-tailed Ionic Surfactants upon Aromatic Nucleophilic Substitution
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Reactions of OH- with 2,4-dinitro-1-chloro-benzene and -naphthalene have been examined in solutions of didodecyldimethylammonium chloride and hydroxide.Rate effects were analysed quantitatively in terms of distribution of reactants between water and the colloidal particles.Second-order rate constants at the surface of the particles are very similar to those in normal aqueous micelles of cetyltrimethylammonium hydroxide, chloride, and bromide and p-octyloxybenzyltrimethylammonium bromide and are slightly higher than in water.Similar observations were made on the reaction of OH- with 2,4-dinitro-1-fluorobenzene.
- Cipiciani, Antonio,Germani, Raimondo,Savelli, Gianfranco,Bunton, Clifford A.,Mhala, Marutirao,Moffatt, John R.
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p. 541 - 546
(2007/10/02)
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- Thermotropic Liquid Crystalline Character and Vesicular Properties of Some Functionalized Long-Chain Di-n-dodecyl Quarternary Ammonium Salts
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In several reports it has been shown that amphiphilic molecules, including phospholipids, which aggregate in solution to form micelles, vesicles and liposomes also exhibit thermotropic liquid crystalline phases.In conjunction with our recent work on the synthesis and characterization of vesicle-forming monomeric and polymerized allyl and diallyl di-n-alkyl quarternary ammonium salts, a series of analogously functionalized derivatives has been prepared.Di-n-dodecyldimethyl quarternary ammonium bromide was employed as the parent compound.The new quarternary ammonium salts were formed by replacing one or both of the methyl groups in the parent compound by groups such as -CH2-CH=CH2, -CH2CH2OH, -CH2COOH, -CH2CH2COOH, or -CH2CH2CH2CN.The existence of liquid crystalline phases in these quarternaries was established by optical microscopy while transition temperatures as well as thermodynamic parameters were determined by DSC.Some of these compounds when dispersed in water and sonicated ultimately formed vesicles the structure of which was observed by electron microscopy.The effect of the various functional groups on the liquid crystalline phase behavior of these compounds exhibits a well defined variation.However, no systematic variation has been observed on the ability of these same functional groups to affect vesicles formation.
- Paleos, C. M.,Margomenou-Leonidopoulou, G.,Babilis, D.,Christias, C.
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p. 121 - 136
(2007/10/02)
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- Effect of Cholesterol on the Stereoselective Hydrolysis in Artificial Membrane Systems
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The catalytic efficiency and enantioselectivity for the hydrolysis of p-nitrophenyl N-dodecanoyl-D(L)-phenylalaninate (2b) in the catalytic system of N-tetradecanoyl-L-histidyl-L-leucine (1b) and didodecyldimethylammonium bromide (3a) were enhanced by addition of cholesterol at an optimum temperature (25 deg C).Furthermore, it is suggested that the hydrophobic interaction between reactants in the bilayer membrane system (3a) might be reduced by adding cholesterol on the basis of isokinetic temperature.It is concluded from these results that the fluidity of the artificial bilayer matrix (3a) varies upon addition of cholesterol.
- Ueoka, Ryuichi,Matsumoto, Yoko
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p. 3774 - 3778
(2007/10/02)
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