摘要:

In this work, we synthesized new reaction intermediates 5-F-alkyl 4-oxa 1-dimethylamino hex-5-en-2-ols which allowed us to obtain, simply and in satisfying yields a broad range of single-chain and double-chain surfactants with two F-alkylated chains or mixed chains, possessing a polymerizable methylene lateral group and at least one hydroxyl function. Their amphiphilic properties were investigated by measuring their surface tension in aqueous solution. The critical micellar concentration (CMC) of some of them could be determined from surface tension curves versus concentration.

ISSN:0193-2691    

DOI:10.1080/01932699408943581

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Effect of n-propylamine addition on the stability of oil-in-water emulsions containing a triisocyanate soluble in the oil phase was investigated. The oil component was di-n-butyl phthalate(DBP) containing Aerosol-OT as an emulsifier. The drop size change with time was measured to estimate the emulsion stability. It was found that the addition of n-propylamine after emulsification accelerated the coalescence of drops for the emulsion with a triisocyanate. The effects of temperature, amine concentration, polarity of oil phase and AOT concentration were established in this study.

ISSN:0193-2691    

DOI:10.1080/01932699408943582

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Surface properties of four proteins having molecular weights less than 5,000 are reported at air/water and alumina/water interface at pH 7.0. Reversibility in the adsorption of these proteins at the alumina/water interface is tested. The adsorption on alumina/water interface has been found to be controlled by electrostatic interaction. Positive adsorption was obtained when protein and alumina surface had opposite charges and negative adsorption was obtained when both protein and surface had same charges. Of the four proteins reversibility in adsorption was observed with the one having the lowest molecular weight of 3100. The adsorption behavior apparently had no correlation with their surface hydrophobic!ty. Time dependent changes in air/water interfacial tension was observed for all the four proteins indicating time dependent loosening of compact protein structure and surface unfolding.

ISSN:0193-2691    

DOI:10.1080/01932699408943583

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The phase behavior of soybean oil, a nonionic surfactant (ethoxylated monodiglycerides) and an aqueous phase of water containing ethanol, and sucrose was investigated at 35 and 40°C. A minimum concentration of 20 wt% ethanol was required for the formation of isotropic solutions. Addition of sucrose to the aqueous phase decreased the amount of ethanol required to form these solutions. The solubilization mechanism of the oil was investigated by small angle x-ray diffraction and polarized light microscopy. A stable lamellar liquid crystalline phase was formed for a mixture of 75/25 surfactant/sucrose solution (2.5 wt% sucrose). This phase was destabilized with increased concentrations of sucrose and liquid crystalline phases having hexagonal structures were favored at 8.75 wt% sucrose. At a ratio of 55/45 wt% of surfactant/sucrose solution (9 wt% sucrose) hexagonal structures were formed and could be destabilized or destroyed by addition of ethanol. The concept of stabilization and destabilization of liquid crystalline mesophases was applied to the solubilization of triglycerides in aqueous solutions. Two microemulsion regions were identified; oil-in-water (L1) and water-in-oil (L2) in systems containing soybean oil, ethoxylated monodiglycerides, and 20 wt% ethanol solution. At 55/45 wt% surfactant/20 wt% ethanol solution,7.5 wt% of soybean oil was solubilized. Addition of 10, 20, and 30 wt% sucrose, at the same ratio of surfactant to ethanol solution, increased the solubility of the oil to 9, 13.5, and 18 wt% respectively. In addition, the size of the L1phase increased and moved to the aqueous corner of the phase diagram and the size of the L2phase decreased.

ISSN:0193-2691    

DOI:10.1080/01932699408943584

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The fluorescence intenstiy ratios (F2/F1) of excimer (F2) to monomer (F1) of probe (pyrene) were measured as a function of the concentration of the surfactant in several systems, which consist of sodium hexadecyl sulfonate (C16As)-anionic surfactant, cetyltrimethylammonium bromide (CTAB)-cationic surfactant and pentaoxyethylene decyl ether (C10E5)-nonionic surfactant. The second CMC values were obtained according to F2/F1˜ surfactant concentration curve break. In addition, we also studied the variation of second CMC vs NaCl concentration. It was found that the second CMC values of C16A5and CTAB decreased with the increase of NaCl concentration. But the present of NaCl had no influence on the second CMC value of C10E5. Results showed that sphere-shaped micelles turn into rod-like micelle at the second CMC. The results were interpreted in terms of diffusion of pyrene molecules and the distribution of pyrene among micelles.

ISSN:0193-2691    

DOI:10.1080/01932699408943585

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Lamellar liquid crystals of perfluoropolyether (PFPE) surfactants of relatively short chain length (average MW 450 and 730) combined with water or formamide were studied by small angle x-ray diffraction (SAXRD) for the variation of interlayer spacing as a function of solvent content. The results indicated significant solvent penetration in the fluorinated lamellae. The results give a contribution to the identification of the role played on association features by the flexibility of the PFPE chain and its large volume due to side perfluoromethyl groups.

ISSN:0193-2691    

DOI:10.1080/01932699408943586

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The phase behavior and oil solubilization capacities of a series of model microemulsion systems have been studied. Phase behavior was studied in systems composed of NaCl brine, sodium dodecyl sulfate, and either 1-butanol, 1-pentanol, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, ethylene glycol monohexyl ether, or diethylene glycol monohexyl ether. It was found that longer chained cosurfactant systems exhibit isotropic behavior over smaller compositional ranges. Whereas the ethylene glycol monohexyl ether system was found to possess two separate isotropic microemulsion-type regions, all other systems were found to possess connected isotropic regions. The one-phase regions in the 1-pentanol system, however, are connected by a narrow channel. Finally, it was determined that increasing the degree of amphiphilicity in the cosurfactant tends to increase the occurrence of liquid crystal phases.

ISSN:0193-2691    

DOI:10.1080/01932699408943587

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

ISSN:0193-2691    

DOI:10.1080/01932699408943588

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor