排序方式: 共有26条查询结果,搜索用时 312 毫秒
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Genty M. Couarraze G. Laversanne R. Degert C. Navailles L. Gulik-Krzywicki T. Grossiord J.-L. 《Colloid and polymer science》2003,282(1):32-40
Spherulites ® are multilamellar vesicles made up of surfactant bilayers. These vesicles would potentially be very useful for the encapsulation and protection of molecules; however, traditional formulations of these vesicles are poor at retaining small hydrophilic molecules (below 1000 g/mol). In this study, we present new systems of Spherulites called complex dispersions. These are prepared by dispersing Spherulites in an oil medium, and then emulsifying this oily dispersion of Spherulites within an aqueous solvent. These new systems provide an additional oil barrier between encapsulated molecules and an external aqueous phase. We have used polarized light optical microscopy, X-ray diffraction and freeze–fracture electron microscopy to study a complex dispersion of Spherulites at all stages of its preparation. We first studied the sheared lamellar phase, followed by the dispersion of the multilamellar vesicles in the oily medium and finally the emulsification of the oily dispersion within the aqueous solvent. We compared our results on lamellar phases with previous results obtained with Spherulites directly dispersible in an aqueous medium. Since the formulation of our lamellar phase included a large percentage of oil as a component, we studied the localization of the oil in the lamellar structure. We also studied the influence of osmotic pressure on complex dispersions, because complex dispersions possess a double structure similar to that of water-in-oil-in-water emulsions and multiple emulsions are known to be sensitive to osmotic pressure. In conclusion, complex dispersions proved to be new potential carriers exhibiting some unique physical properties. 相似文献
3.
M. C. Abreu M. Alimi C. Baglin A. Baldit G. P. Barreira M. Bedjidian P. Bordalo S. Borenstein J. Britz A. Bussiere P. Busson A. Casaca R. Cases J. Castor C. Charlot B. Chaurand D. Contardo E. Descroix A. Devaux J. Fargeix X. Felgeyrolles P. Force L. Fredj J. M. Gago C. Gerschel P. Gomes P. Gorodetzky J. Y. Grossiord A. Guichard J. P. Guillaud R. Haroutunian L. Kluberg L. Kraus G. Landaud I. Linck C. Louren?o A. Maio L. Peralta M. Pimenta J. R. Pizzi C. Racca S. Ramos A. Romana R. Salmeron A. Sinquin P. Sonderegger J. Varela NA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1988,38(1):129-133
The like-sign dimuons copiously recorded in the NA 38 experiment both inp-U and O?U reactions at 200 GeV/nucleon are interpreted as resulting from decays of π andK mesons in comparable proportions. The ++/?? ratio is large (?1.7) and ascribed to theK + being more copiously produced than theK ?. Both the average transverse momentum and the ++/?? ratio are comparable forp-U and O?U reactions, and both increase only slightly with the transverse energyE T . 相似文献
4.
Study of mass transfer in oil-water-oil multiple emulsions by differential scanning calorimetry 总被引:1,自引:0,他引:1
Avendano-Gomez JR Grossiord JL Clausse D 《Journal of colloid and interface science》2005,290(2):533-545
A multiple emulsion of the type O1/W/O2 is studied experimentally by means of differential scanning calorimetry (DSC). The aim of this work is to characterize and measure the time-dependent changes within the emulsion. In particular, interest is focused to quantify the concentration changes in the internal and external phases of the O1/W/O2 multiple emulsion. In order to accomplish the objective, the measurement and analysis carried out by DSC are based on the crystallization behavior of the emulsion. A volume of a few mm3 is periodically removed from the O1/W/O2 multiple emulsion. The sample is submitted to steady cooling and the crystallization thermogram is recorded. The experimental data provided by the crystallization thermogram makes it possible to quantify the crystallized mass for both phases, the internal and the external. In addition, the composition in each phase can also be deduced from the thermogram. To deduce the composition, a diagram of crystallization temperatures is elaborated, employing several mixtures of known composition. In addition to the main objective previously mentioned, the influence of formulation parameters such as surfactant concentration in the aqueous phase and the mass ratio of the internal and external phases are also analyzed. The experimental results made it possible to conclude that a mass transfer took place from the internal phase toward the external phase; this transfer is caused by the composition difference on both sides of the aqueous membrane. In this work we analyzed the mass transfer in the multiple emulsion carried out by a composition gradient through the aqueous membrane. The most likely mechanism of mass transfer through the aqueous membrane is a solution-diffusion of tetradecane enhanced by the micelles of the surfactant Tween 20. The model of mass transfer confirms that the osmotic pressure difference controls the kinetics of tetradecane transfer. It is also confirmed that an increment of surfactant concentration in the aqueous phase allows a faster kinetics of the tetradecane transfer. 相似文献
5.
By assuming simplified hypotheses which result from the molecular analysis of Doi-Edwards, it is possible to propose rheological methods for characterizing molar weight distribution of entangled polymeric liquids. The generalized exponential distribution is especially concerned. Theoretical expressions of rheological parameters are derived, and their numerical values are calculated in special cases. A numerical method of discrimination and identification of these special distributions is proposed. 相似文献
6.
A. Brockstedt I. Bergquist L. Carln L. P. Ekstrm B. JakobssonC. Ellegaard C. Gaarde J. S. LarsenC. GoodmanM. Bedjidian D. Contardo J. Y. Grossiord A. Guichard J. R. PizziD. Bachelier J. L. Boyard T. Hennino J. C. Jourdain M. Roy-StephanM. Boivin T. HasegawaP. Radvanyi 《Nuclear Physics A》1991,530(3-4):571-604
Data for the (3He, t) reaction at 900 MeV and 2 GeV on the targets 26Mg, 40Ca, 48Ca, 54Fe, 90Zr and 208Pb are presented. A multipole decomposition for the data at 900 MeV has been made and the different distributions have been analysed. From the L = 0 cross section the Gamow-Teller strength distributions are extracted and compared with (p, n) data. The L = 1 and 2 distributions are analysed in a schematic model which describes the general systematics fairly well. The spectra at 2 GeV and Θ = 4° show for all targets a well-developed quasi-elastic peak. The A-dependence of the cross section is analysed in a simple model. 相似文献
7.
Rheological analysis of highly concentrated w/o emulsions 总被引:2,自引:0,他引:2
Nathalie Jager-Lézer Jean-Francois Tranchant Valérie Alard Can Vu Pierre Cyrill Tchoreloff J.-L. Grossiord 《Rheologica Acta》1998,37(2):129-138
A series of highly concentrated lipophilic cosmetic emulsions were analysed, in order to determine their rheological and
textural properties, as a function of their microstructure. The originality of this study lies in the methodology used, especially
the shear-stress scanning analysis. The results of a very powerful and comprehensive dynamic rheological analysis suggest
the existence of two critical volume fraction values: besides the “close-packed” value φ
c
, a “slack-packed” value φ0, close to 0.60 could be demonstrated. It has been shown that the close-packed structure is stable under shear; in constrast,
the slack-packed configuration, defined as φ0<φ<φ
c
is unstable under shear. A comparison with theoretical models, especially that of Princen, showed good agreement and allowed
the close-packed value φ
c
to be defined more precisely as 0.67. The gap between 0.67 and 0.74 is probably indicative of a highly polydisperse distribution,
as confirmed by microscopic analysis. Flow experiments confirmed the validity of Princen‘s model.
Received: 20 February 1997 Accepted: 20 January 1998 相似文献
8.
A.K. Jain J.Y. Grossiord M. Chevallier P. Gaillard A. Guichard M. Gusakow J.R. Pizzi 《Nuclear Physics A》1973,216(3):519-540
The 6Li(d, 2d)4He and 6Li(d, dα)2H reactions were performed at 27 MeV. Analyses of these and the 42.8 and 55 MeV 6Li(α, 2α)2H reactions were performed using distorted wave and plane wave impulse approximations. The kinematic and potential coupling approximations to final state three-body Schrödinger equation and the post and prior form approximations to off-shell scattering cross section were studied for the three reactions. It was found that only the kinematic coupling and post form approximations could be used for the consistent analyses of the three reactions. The effects of distortions and localization of the reactions were investigated. Manifestations of deuteron cluster deformation were noticed in the analyses of the three reactions. 相似文献
9.
Grossiord N Schoot Pv Meuldijk J Koning CE 《Langmuir : the ACS journal of surfaces and colloids》2007,23(7):3646-3653
To determine the surface coverage of exfoliated carbon nanotubes by surfactant molecules, we propose four experimental methods based on thermogravimetric analysis, UV-vis spectroscopy, surface tension measurements, and a variant of Maron's titration. We apply all four methods to aqueous mixtures of carbon nanotubes and the surfactant sodium dodecyl sulfate and consistently find a surface coverage of between 1.5 and 2 g of surfactant per gram of carbon nanotubes. This corresponds to slightly more than two SDS molecules per square nanometer, which is comparable to the known maximum packing density of SDS at the air-water interface. 相似文献
10.
L. Payet A. Ponton J. -L. Grossiord F. Agnely 《The European physical journal. E, Soft matter》2010,32(2):109-118
The local structure and the viscoelastic properties of semi-interpenetrated biopolymer networks based on cross-linked chitosan
and poly(ethylene oxide) (PEO) were investigated by Small Angle Neutron Scattering and rheological measurements. The specific
viscosity and the entanglement concentration of chitosan were first determined, respectively, by capillary viscosimetry and
steady-state shear rheology experiments performed at different polymer concentrations. Mechanical spectroscopy was then used
to study the gelation process of chitosan/PEO semi-interpenetrated networks. By fitting the frequency dependence of the elastic
and loss moduli with extended relations of relaxation shear modulus around the sol-gel transition, it was shown that the addition
of PEO chains had a significant effect on the viscoelastic properties of aqueous chitosan networks but no effect on the gelation
time. The improvement of mechanical properties was in accordance with the correlation length decrease deduced from Small Angle
Neutron Scattering experiments. 相似文献