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Showing papers in "Journal of Dispersion Science and Technology in 1999"


Journal ArticleDOI
TL;DR: In this article, the authors investigated the viscoelastic properties of heat-set whey protein emulsion gels containing active filler and inactive filler (surfactant-covered droplets) at small and large deformations using a controlled stress rheometer.
Abstract: Viscoelastic properties of heat-set whey protein emulsion gels containing active filler (protein-covered droplets) and inactive filler (surfactant-covered droplets) have been investigated at small and large deformations using a controlled stress rheometer. Data are reported as a function of protein concentration, oil volume fraction, and average emulsion droplet size. The active filler enhances the gel strength, whereas the inactive filler reduces the gel strength. The higher the elastic modulus of the protein gel matrix, the less the effect of the active filler, but the greater the effect of the inactive filler (and vice versa). Higher oil volume fraction and reduced particle size both intensify the effect of the filler. The large deformation behaviour of a heat-set protein gel or a heat-set emulsion gel containing up to 20 vol% oil is entropic in character, whereas an emulsion gel of higher filler content behaves more like a typical enthalpic particle gel.

180 citations


Journal ArticleDOI
TL;DR: Gum Arabic is the only gum in use in dilute emulsion systems which was proved to be a good emulsifier - adsorbing onto oil-water interfaces and imparting steric stabilization.
Abstract: Hydrocolloids are water-soluble biopolymers consisting of high molecular weight polysaccharides. For generations, these biopolymers were also termed gums or stabilizers imparting viscosity, gelification and long-term stability to food systems. Some hydrocolloids were also considered as emulsifying agents, since they help to form and stabilize oil-in-water emulsions. Only in the last two decades questions have been raised as to the mode of their action in low viscosity and low concentrations dispersed systems consisting of oil and water. Gum Arabic is the only gum in use in dilute emulsion systems which was proved to be a good emulsifier - adsorbing onto oil-water interfaces and imparting steric stabilization. However, other gums have been known to reduce surface and interfacial tensions, to adsorb onto solid surfaces and to improve stability of oil-in-water emulsions. Only recently attention has been paid to the structure-surface activity relationship between the gums and their emulsification abi...

116 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the effect of oil droplet size on the oxidation rate of DHA monodispersed emulsion with xanthan and found that the peroxide value (POV) of the Xanthan-free emulsion reached 10meq/ kg at 20 days.
Abstract: We investigated the effect of oil droplet size on the oxidation rate of DHA monodispersed emulsion with xanthan. Xanthan-free emulsions creamed rapidly but no creaming was observed in the emulsions containing xanthan over 8 weeks. While the peroxide value (POV) of the xanthan-free emulsion reached 10meq/ kg at 20 days, that of both emulsion systems containing xanthan changed little during the first 20 days. The POV for the emulsion with small droplet was higher than that for the emulsion with large droplet.

74 citations


Journal ArticleDOI
TL;DR: In this article, the effect of different exchangeable cation on the adsorption amount of methylene blue was determined, and it was shown that the effect depends on the cation type.
Abstract: Adsorption of Methylene Blue ( MB) on Na-, Fe- and Al-montmorillonite suspensions at 298.15 K were studied. The effect of different exchangeable cation on the adsorption amount of MB was determined...

73 citations


Journal ArticleDOI
TL;DR: In this paper, a cubic and hexagonal phase is compared to liposomal dispersions, and it is concluded that an important application of the cubic particles will involve encapsulation of proteins and protection of their native conformation.
Abstract: Aqueous dispersions of colloidal aggregates of liquid-crystalline lipid-water phases are described. The lamellar liquid-crystalline phase can form liposomal dispersions, which are wellknown from extensive studies of these particles in drug delivery. Less is known about dispersions of cubic and hexagonal phases. The preparation of such colloidal dispersions, their structure and physical properties are summerised. The dispersed cubic phase is compared to liposomal dispersions, and it is concluded that an important application of the cubic particles will involve encapsulation of proteins and protection of their native conformation.

73 citations


Journal ArticleDOI
TL;DR: The role of asphaltenes in stabilizing water-in-crude oil emulsions is extremely well established as discussed by the authors, and the role of chemistry in governing the strength of these lateral inter-asphaltene interactions is still relatively unknown.
Abstract: The role of asphaltenes in stabilizing water-in-crude oil emulsions is extremely well established. The mechanism appears to be one in which planar, disk-like asphaltene molecules aggregate through lateral intermolecular forces to form primary aggregates or micelles which are interfacially active. These aggregates — upon adsorbing at the oil-water interface — crosslink through physical interactions to form a viscoelastic network, which has been characterized by some as a “skin” or a “plastic film”. The strength of this film, as gauged by shear and elastic moduli, seems to correlate well with water-in-oil emulsion stability. What is still relatively unknown is the role of chemistry in governing the strength of these lateral inter-asphaltene interactions. The candidate interactions include π-bonding between the delocalized electrons in the fused aromatic ring core, H-bonding between proton donors and acceptors imbedded in the asphaltenic cores, and metal-electron interactions between, for example, h...

44 citations


Journal ArticleDOI
TL;DR: In this article, the phase behavior of surfactant-oil-water systems and emulsion properties (type, droplet size and stability) were studied as a function of the surfactants concentration.
Abstract: Very fine emulsions with droplet size in the sub-micron range, often called miniemulsions, are prepared by the moderate (magnetic) stirring of a system undergoing a dynamic transitional inversion driven by a continuous change in physico-chemical formulation (here temperature). Near optimum formulation for three-phase systems, the ultralow interfacial tension favors the drop breaking rate, and fine emulsions can be made. However, this region is also known for its rapid coalescence rate. Thus, a high enough stability can be attained only by shifting the formulation away from optimum as soon as the emulsion is made. Moreover, a rapid change in formulation through the three-phase region also results in a separation phenomenon that can be harnessed to produce ultra fine droplets. The phase behavior of surfactant-oil-water systems and emulsion properties (type, droplet size and stability) are studied as a function of surfactant concentration (2 wt.% and 6 wt.%), for two different nonionic surfactants (polyoxyethylene triterbutyl ethers and sorbitan derivatives) with HLB ranging from 4 to 16. Kerosene and paraffin oil are used as oil phases. The transitional inversion form W/O to O/W is induced by a rapid cooling of the stirred systems from above to below the optimum temperature for three-phase behavior. Miniemulsions are attained when the surfactant concentration is high enough, and when the temperature quenching span covers an appropriate range related to phase behavior.

43 citations


Journal ArticleDOI
TL;DR: In this paper, a commercial humic acid (HA) up to 50 mg L−1 has been found to decrease the degradation rate of some model pollutants, namely phenol, 2,4-dichlorophenol and tetrachloromethane.
Abstract: Photocatalysis over irradiated Ti02 has been proved to efficiently abate more than 80% of the organic carbon pertaining to a commercial humic acid (HA). The presence of HA up to 50 mg L−1 has been found to decrease the degradation rate of some model pollutants, namely phenol, 2,4-dichlorophenol and tetrachloromethane. However, the total organic carbon measurements and chloride evolution ensure that the disappearance of the initial pollutants is not due to binding to HA structure, but to an efficient mineralization process. HA' s are able to scavenge both the oxidative and the reductive active species as shown by the inhibiting effect on the rate of disappearance of phenol and 2,4-dichlorophenol (essentially oxidative), and of CCI4 (initially reductive).

38 citations


Journal ArticleDOI
TL;DR: In this article, the solubilization of water in w/o microemulsions formed with mixed-surfactants containing one anionic and one cationic surfactant and alcohol was studied as a function of alkyl chain length of oil.
Abstract: The solubilization of water in w/o microemulsions formed with mixed-surfactants containing one anionic and one cationic surfactant and alcohol was studied as a function of alkyl chain length of oil (C6 to C 16 ), mixed-surfactant (sodium dodecyl sulfate, SDS, and cetyltrimethylammonium bromide, CTAB, or cetylpyridinium bromide CPB), and alcohol (1-butanol, 1-pentanol, 1-hexanol). The results show that the solubilization of water in microemulsion systems increases significantly with the mixed-surfactants due to the synergistic effect resulting from the strong Coulombic interactions between cationic and anionic surfactants and the solubilizing efficiency increases as the chain length or concentration of alcohol increases. With increasing the oil chain length the solubilization for water increases, decreases, and has the chain length compatibility effect when the systems contain 1-hexanol, 1-butanol, 1-pentanol, respectively. The total solubilizing capacity increases as the surfactant concentration (keep the ratio of SDS to butanol constant) increases.

36 citations


Journal ArticleDOI
TL;DR: In this article, an extended C+ multiple emulsion region and a skinked A+ W/O emulsion zone were found for a mixture of carboxylic acid and its sodium salt.
Abstract: Surfactant-oil-water systems in which the surface active substance is a mixture of carboxylic acid and its sodium salt (soap), exhibit emulsion property maps that are consistent with the phase behavior and the general emulsion phenomenology. However they present specific features such as an extended C+ multiple emulsion region and a skinked A+ W/O emulsion zone. In this case the aqueous phase pH drives the relative hydrophilicity of the acid/salt mixture at interface and plays the role of the most sensitive formulation variable. Studied systems contain C10 to C14 carboxylic acid, NaCl brine and a light distillation cut, as well as alcohols.

28 citations


Journal ArticleDOI
TL;DR: In this article, the phase behavior of Eucalyptus oil/ Tween 20/ Butanol/ Water and Eucaliaptusoil/Tween 20 / Cinnamic Alcohol/ Water systems have been studied in detail.
Abstract: The phase behavior of Eucalyptus oil/ Tween 20/ Butanol/ Water and Eucalyptus oil/ Tween 20/ Cinnamic Alcohol/ Water systems have ben studied in detail. Both triangular and tetrahedral representations have been considered to understand the topological nature of the multicomponent mixtures. Shear viscosities of typical multiphasic compositions have been measured at different rates and temperatures. The samples have undergone shear thinning. The effect of temperature on the volumes of multiphasic compositions have been also investigated both increase and decrease of the extents of different phases have been witnessed. The enthalpy of dissolution of both water and oil in presence of amphiphile solutions in oil and water respectively have been determined calorimetrically. Considering the phase separation point to be the point of maximum solubility of microdroplets, the free energies and hence entropies ofsolution have been estimated. The above phy.sicochemical features have been also examined in pres...

Journal ArticleDOI
TL;DR: The formation of lyotropic mesophases (liquid crystals) in four binary systems n-alkyl glycosides/water was examined in dependence on surfactant concentration, temperature and the chain lengths as discussed by the authors.
Abstract: The formation of lyotropic mesophases (liquid crystals) in four binary systems n-alkyl glycosides/water was examined in dependence on surfactant concentration, temperature and the chain lengths (alkyl = heptyl, octyl, nonyl, decyl). The binary phase diagrams were established and the enthalpies of phase transitions were measured. The following phase transitions were detected by texture observation and calorimetry: hexagonal phase H, lamellar phase L, cubic phase Q, gel phase G and crystalline phase C. The positions of the corresponding regions of these phases in the phase diagram were determined. Sequence of phases and the localization of the phase regions were depended on the chain length of the alkyl group. So in the binary system n-decyl-β-D-glucoside/water the H-phase was not observed.

Journal ArticleDOI
TL;DR: In this article, the conformation of the lung surfactant lipid bilayer (termed tubular myelin) is shown to fit an infinite periodic surface, which is free from self-intersections and with zero or close to zero average curvature.
Abstract: The conformation of the lung surfactant lipid bilayer (termed tubular myelin) is shown to fit an infinite periodic surface, which is free from self-intersections and with zero or close to zero average curvature. A single lipid bilayer is curved in space, forming a tetragonal structure (CLP) with tubular units, the walls of which are close to planar and parallel to two orthogonal directions. A cryo transmission electron microscopy (cryo-TEM) study of the alveolar surface layer from rabbit was performed. Direct deposition of the surface layer on the microscopy grid indicates that the surface zone consists of a homogeneous phase. The cryo-TEM texture of the bilayer is consistent with earlier reported electron microscopy observations of dispersed aggregates in lung washings. It is shown how the interface towards air can be formed by opening up the phase along lipid methyl end groups. The model is fundamentally different from earlier proposals, involving a “free” lipid-protein monolayer at the air/wat...

Journal ArticleDOI
TL;DR: A new dispersion process to prepare liposomes without the usage of organic solvents and detergents is developed, using a microfludizer for the extrusion and homogenization of aqueous dispersion of phospholipids, and a modified evaporator in order to increase lipid thin film surface area.
Abstract: Liposomes are microscopic vesicles composed of phospholipid bilayers surrounding discrete aqueous compartment. Eventhough phospholipid bilayers are formed spontaneously in water, their conventional preparation methods involve either organic solvents or detergent molecules. Organic solvents may create a serious safety problem during liposome manufacturing especially on a large scale and can cause denaturation of proteins and affect the membrane properties. Liposomes are very promising carriers for protein drugs which have aroused great interests in the field of pharmaceutics in these recent years. The objective of this study was to develop a new dispersion process to prepare liposomes without the usage of organic solvents and detergents. The approach involved the usage of a microfludizer for the extrusion and homogenization of aqueous dispersion of phospholipids, and a modified evaporator in order to increase lipid thin film surface area. The properties of the liposomes prepared by the novel metho...

Journal ArticleDOI
TL;DR: In this article, the effect of alcohols on the silica particle size distributions and on hydrophobicity of silica surface was tested, and the precipitated silicas were subjected to physicochemical, structural and microscopic evaluation, and their surface properties were examined.
Abstract: Silicas were obtained using a precipitation technique from metasilicate solution with an acidic agent. The precipitation process includes formation of silica particles and their aggregation. Alcohol solutions were used in the production process of the highly dispersed silicas, resulting in a partial blocking of the silica surface silanol groups and, thus, in a decreased hydrophilicity of silica. The precipitated silicas were subjected to physicochemical, structural, and microscopic evaluation, and their surface properties were examined. The effect of alcohols on the silica particle size distributions and on hydrophobicity of silica surface was tested.

Journal ArticleDOI
TL;DR: In this paper, the C-potential of anionic surfactant micelles is estimated for the study of adsorption of solutes onto the micellar surface, which causes a reduction of the net electrostatic charge.
Abstract: The estimation of the C-potential of ionic surfactant micelles may be useful for the study of adsorption of solutes onto the micellar surface, which causes a reduction of the net electrostatic charge. This work presents results on the variation of ζ-potential of alkylsulfate and fatty carboxylate micelles with the bulk concentrations of Al3+ and Ca2+ cations. Combined with results from the literature about the effect of micellar surfactant concentration on reducing surfactant precipitation in the presence of polyvalent cations, these allow to conclude that micelles of anionic surfactants will have a higher chance of electroneutralization of their surface charge by adsorbing cations if the end functional group of the surfactant is smaller.

Journal ArticleDOI
TL;DR: In this paper, the influence of noncharged and especially charged polymers on structure formation in mesoscopic organized surfactant/alcohol/water systems is investigated, and it is shown that the addition of a cationic polyelectrolyte to the SDS based w/o-microemulsion does not lead to a macroscopic phase separation.
Abstract: The influence of noncharged and especially charged polymers on structure formation in mesoscopic organized surfactant/alcohol/water systems is investigated. Cationic polyelectrolytes can be incorporated into the liquid crystalline SDS/decanol/water system keeping up the lamellar phase. The “usual” swelling of the bilayer can suppressed and an adsorption of the polycation at the head groups of the SDS bilayer is assumed. The incorporation of poly-anions is more complicated and macroscopic phase separation can be observed. A characteristic feature of a system with two polymers is the appearance of two coexisting lamellar phases, i. e. a swellable and non-swellable one. In the SDS/pentanol/water/xylene system the addition of a hydrophobic polymer can induce the formation of a bicontinuous phase channel. Surprisingly, the addition of a cationic polyelectrolyte to the SDS based w/o-microemulsion does not lead to a macroscopic phase separation.

Journal ArticleDOI
TL;DR: In this paper, two techniques for extraction and purification were excersized in order to obtain a purified saponins extract from several sources (fenugreek, soybean, locust bean and sesame).
Abstract: Two techniques for extraction and purification were excersized in order to obtain a purified saponins extract from several sources (fenugreek, soybean, locust bean and sesame). The results indicate that fenugreek steroid saponins extract has the best surface properties and reduces the surface tension to 33.3 mN/m and the tetradecane-water interfacial tension from 44 mN/m to 7.5 mN/m. The HLB value was evaluated and found to be 18. Three different types of oil (n-tetradecane, soybean oil, tricaprylin) were emulsified with a 6 wt% aqueous solution of saponins to give an average droplet size of 0.7 μm (yet stable after month). An effective synergism is seen when these emulsions were prepared with sucrose fatty acid esters as co-surfactant. Furthermore, the foaming power was evaluated.

Journal ArticleDOI
TL;DR: In this paper, the conductances of Tetradecyltrimethylammonium bromide (TTAB) + dodecyltrimethyl bromium (DTAB), over the entire mole fraction range of TTAB, were measured in aqueous polyethylene glycol 1000 (PEG) containing 1, 2, 5 and 10 wt% of PEG at 30 °C.
Abstract: The conductances of tetradecyltrimethylammonium bromide (TTAB) + dodecyltrimethylammonium bromide (DTAB) mixtures over the entire mole fraction range of TTAB (αOITTAB) were measured in aqueous polyethylene glycol 1000 (PEG) containing 1, 2, 5 and 10 wt% of PEG at 30 °C. From the conductivity data, various micellar parameters were computed. The results have been explained on the basis of the medium effects as well as the adsorption of additive molecules at micelle-solution interface. The non-ideality in TTAB+DTAB mixtures was evaluated by using the regular solution theory and Motomura's formulation based on the excess thermodynamic quantities. It has been found that the regular solution interaction parameter (β) and micellar mole fraction (¯x m 2) remain almost unaffected even in the presence of upto 10 wt% of PEG. These results suggest that the additive remains only in the aqueous phase and perhaps only changing the environment surrounding the micelles by adsorbing at the micelle-solution interface.


Journal ArticleDOI
TL;DR: In this article, the bicontinuous structure of the micro-emulsion was confirmed by means of self-diffusion coefficient on NMR measurement, and a larger solubilization capability of oil is attained to a mixed mono- and poly-dodecanoate system than that of the middle chain alcohol.
Abstract: Sucrose monoalkanoates (SE) form microemulsions by mixing with lipophilic cosurfactants such as the middle-chain alcohols, or sucrose polyalkanoates. In the case that sucrose monododecanoate is combined with hexanol, a middle-phase microemulsion is produced and coexists with excess water and oil phases at optimum mixing fraction of SE and hexanol. The bicontinuous structure of the microemulsion was confirmed by means of self-diffusion coefficient on NMR measurement. A larger solubilization capability of oil is attained to a mixed mono- and poly-dodecanoate system than that of the middle-chain alcohol. It is probably due to the location of most of surfactant molecules at the micro-interface inside the microemulsion. In this system, instead of forming a three-phase region, a lamellar liquid crystal intrudes into multi-phase region since the surfactant layer is rather rigid as which was supported by the results of SAXS and ESR measurements. Further addition of a short-chain alcohol such as propanol ...

Journal ArticleDOI
TL;DR: In this paper, the number of nuclei produced in the early stage of polymerization was found to be constant during the remainder of the polymerization, which is attributed to the low mobility of the growing polymer particles.
Abstract: Monodisperse microspheres of polystyrene with diameters in the size range I -2.2(μm) were prepared by the radiation-induced dispersion polymerization. The polystyrene microspheres by radiation-induced in the presence of co- solvent (DMSO-H2) was investigated as functions of various factors such as irradiation time, irradiation dose rate, the amount of water and on or not stirring et al. The number of the nuclei produced in the early stage of the polymerization was found to be constant during the remainder of the polymerization. The nuclei grow to be monodisperse polymer particles without aggregation under appropriate conditions, This is attributed to the low mobility of the growing polymer particles.

Journal ArticleDOI
TL;DR: In this article, the zeta-potential of silica, copper, platinum and gold particles have been measured as a function of pH, and the isoelectric points were found to be at pH 3.0, 5.8, 3.5, respectively.
Abstract: The zeta-potentials of silica, copper, platinum and gold particles have been measured as a function of pH. The isoelectric points were found to be at pH 3.0, 5.8, 3.0 and 3.5, respectively. In the pH range 3.0 to 5.8 copper and silica particles are oppositely charged and accordingly the coating of silica with copper particles could be demonstrated. In the case of gold and platinum the sign of the charge is such that direct adhesion to silica particles cannot be expected and this was also demonstrated in the case of platinum.

Journal ArticleDOI
TL;DR: In this paper, the large surface diffusitivities of polyvalent ions adsorbed on negatively charged liposomes are found combining measurements of conductivity and electrophoresis.
Abstract: Ionic surface diffusitivity is important parameter for the electrostatic interaction between colloid particles and hence its measurement is a new important factor for the surface characterization of colloid particles. If the adsorbed ion mobility is small the approximation of the interaction at constant charge can be valid,but in opposite case the charge regulation occurs during their interaction. The large surface diffusitivities of polyvalent ions adsorbed on negatively charged liposomes are found combining measurements of conductivity and electrophoresis. At a rather low surface charge and high adsorbability of polyvalent cations, the diffuse-layer charge can be very small in comparison with the Stern-layer charge, which can predominate in surface conductivity and provide information about the diffusitivity of adsorbed ions if it is not small. An efficient and simple method for the discrimination between small and large surface diffusitivities of adsorbed ions based on the determination of bot...

Journal ArticleDOI
TL;DR: In this article, the formation of silver nanoparticles by reduction of silver ions by sodium borohydride in non-ionic water-in-oil microemulsion was investigated as a function of structure of the surfactant.
Abstract: The formation of silver nanoparticles by the method of reduction of silver ions by sodium borohydride in non-ionic water-in-oil microemulsion was investigated as a function of structure of the surfactant Three types of non-ionic surfactants were selected differing in the chain length of the oxyethylene groups for example: NP-5, NP-9 and NP-11 The silver nanoparticles were characterized by UV-Visible Absorption Spectroscopy and Transmission Electron Microscopy TEM The results of this study showed that the panicle size is relatively smaller incase of NP-9 while for NP-5 and NP-11 the sizes are comparable This obsevation is explained on the basis of structure of the droplets and the influence of Intermicellar exchange on nucleation and growth of particles

Journal ArticleDOI
TL;DR: In this article, a monodisperse nonionic surfactant based on lysine with two different fatty acid chains in the hydrophobic part and one or two polyoxyethylene methoxy capped chain s (EOn-Me) was synthesized and their physicochemical and toxicity properties were compared to the symmetrical homologs with the same number of methylene groups in the acyl fatty chains.
Abstract: New monodisperse nonionic surfactant molecules based on lysine with two different fatty acid chains in the hydrophobic part and one or two polyoxyethylene methoxy capped chain s (EOn-Me) in the hydrophilic head group were synthesized and their physicochemical and toxicity properties were compared to the symmetrical homologs with the same number of methylene groups in the acyl fatty chains. Our findings indicate that the asymmetry studied results in higher surface active properties and in a greater capacity for micellization when compared with their symmetrical analogs, albeit with a slight increase in toxicity.

Journal ArticleDOI
TL;DR: In this paper, the adsorption properties and surface charge creation for the stearic acid and octadecane/aqueous electrolyte solutions are considered, and the hairy structure of surface charge for these systems was confirmed on the basis of potentiometric titration, ion adsorsorption and electrophoretic measurement data.
Abstract: The adsorption properties and surface charge creation for the stearic acid and octadecane/aqueous electrolyte solutions are considered. The hairy structure of surface charge for these systems was confirmed on the basis of potentiometric titration, ion adsorption and electrophoretic measurement data. For the system with stearic acid the reaction of ionization and complexation of carboxyl groups of stearic acid molecules from subsurface layer are responsible for the creation of surface charge and adsorption properties. The surface charge at octadecane particle is probably the results in adsorption and orientation of water molecules at the interface.

Journal ArticleDOI
TL;DR: In this paper, the temperature-induced percolation behaviors of AOT reverse micelles in the presence of nonionic surfactants have been studied and the effects of water content, solvent and concentration of electrolyte in solubilized water have also been investigated.
Abstract: The temperature-induced percolation behaviors of AOT reverse micelles in the presence of nonionic surfactants have been studied. The effects of water content, solvent and concentration of electrolyte in solubilized water have also been investigated. It was found that the percolation temperature of AOT reverse micelles was decreased by adding nonionic surfactants, and more pronounced effects were observed with the increase of EO chain length and content of nonionic surfactants. The increase of molecular volume of the solvent and the increase of concentration of the added NaCl electrolyte have shown assisting and resisting effects on the process, respectively. The apparent hydrodynamic diameter of droplets of different mixed reverse micelles has been measured using dynamic light scattering, by which the percolating mechanism of mixed reverse micelles was discussed in combination with the results obtained from conductivity measurements.

Journal ArticleDOI
TL;DR: In this paper, the diffusion coefficient of the micelle, the first CMC and the second CMC of Triton X-100 are determined by cyclic voltammetry without any probe.
Abstract: The diffusion coefficient of the micelle, the first CMC and the second CMC of Triton X-100 are determined by cyclic voltammetry without any probe. The first CMC and the second CMC of Triton X-100 are 3.1x lO−1 and 1.3× 10−1 respectively. The viscosity of the micelle solution, the micellar aggregation number and the micellar size increase but the diffusion coefficient decreases with Triton X-100 concentration increasing. The mechanism of the electrochemical reaction of Triton X-100 at platinum electrode is deduced by measurements of conductivity, pH and cyclic voltammetry.

Journal ArticleDOI
TL;DR: In this article, the phase diagram of the system formed by diethanol ammonium dodecanoate (DCD ) / n-butano1 / paraffin oil (LP) /water was determined.
Abstract: The phase diagram of the system formed by diethanol ammonium dodecanoate ( DCD ) / n-butano1 / paraffin oil (LP) /water was determined The lyotropic liquid crystal region was confirmed and the use of liquid crystal as lubricant on aluminum alloy surfaces was studied. The effect of the liquid crystal structure on the tribological properties was also evaluated. Comparing the wear scar widths and the vertical loads of liquid crystal with that of a commercial grease. The lamellar liquid crystal showed a higher load carrying capacity relative to the commercial grease.