Emulsions

To control stability of an emulsified system is to control funda mental processes like sedimentation (or creaming), flocculation, coalescence and Ostwald ripening. In these processes, a knowledge of fundamental physico-chemical properties of stabilizers, (surfactants or polymers) either as monomers or in an aggregated form is required. During the NATO ARW on "Emulsions - A Funda mental and Practical Approach" organized on June, 24. and 25. 1991 in Bergen, Norway, attention was focussed on emulsions from both theoretical and practical aspects. The workshop gathered' 95 participants from 14 different countries. The lectures at the workshop covered from a fundamental point of view general aspects on stability, interfacial adsorption mecha nisms, interfacial rheology, direct measurements of surface forces and bulk rheological properties of emulsions, and self diffusion properties as measured by means of NMR. With re9ard to applications the fields of food, crude oil and pharmaceutlcal emulsions were covered. For ,the food emulsions a central topic is the role of the proteins at the WIO interface, their conformations and mechanisms b Yen which they can be replaced at the interface (competitive adsorptlon). For water-in-crude oil emulsions the mechanisms behind the reso lution of water are of large technical importance. Characteri zations of the stabilizing asphaltene fraction, physico-chemical properties of destabilizing surfactants and the interplay between asphaltenes and waxes at the WIO interface were discussed. Stuctures of pharmaceutical emulsions and creams were charac terized as well as nonionic vesicle drug administration systems. In addition fluorocarbon emulsions acting as blood substitutes were also presented.

Texte du rabat

The fundamental side of this book covers general aspects of stability, interfacial absorption mechanisms, interfacial rheology, direct measurements of surface forces and the bulk rheological properties of emulsions, and self-diffusion properties as measured by NMR. The applications side covers the fields of food, crude oil and pharmaceutical emulsions. br/ A central topic in the study of food emulsions is the role played by proteins at the water/oil interface, their conformations, and the mechanism by which they can be replaced at the interface (competitive absorption). The mechanisms underlying the resolution of water are of crucial importance in the study of water-in-crude-oil emulsions. The book therefore discusses the characterization of the stabilizing asphaltene fraction, the physicochemical properties of destabilizing surfactants, and the interplay between asphaltenes and waxes at the W/O interface. br/ The structures of pharmaceutical emulsions and creams are characterized, as well as nonionic vesicle drug administration systems. Finally, fluorocarbon emulsions acting as blood substitutes are also discussed. br/

Contenu
Emulsion Stability.- Adsorbed Protein Layers in Food Emulsions.- Emulsions in the Food Industry.- Adsorption Structures in Food Emulsions.- The Role of Low-Polar Emulsifiers in Protein-Stabilized Food Emulsions.- Surfactant Induced Flocculation of Emulsions.- The Resolution of Emulsions, Including Crude Oil Emulsions, in Relation to HLB Behaviour.- Interfacial Rheology of Surfactant Solutions.- Studies of Interactions between Surfaces Immersed in Crude Oils.- Interfacial Aspects of Water-in-Crude Oil Emulsion Stability.- Water-in-Crude Oil Emulsions from the Norwegian Continental Shelf. Part VI. Diffuse Reflectance Fourier Transform Infrared Characterization of Interfacially Active Fractions from North Sea Crude Oil.- Rheological Properties of Emulsion Systems.- Pharmaceutical Emulsions and Creams.- Perfluorochemical Emulsions as Blood Substitutes.- Characterization of Niosomes.- NMR Self-Diffusion Studies of Emulsion Systems. Droplet Sizes and Microstructure of the Continuous Phase.- Organic Ions as Demulsifiers.- Surface Forces and Emulsifiers.- Destabilization of Water-in-Oil Emulsions.