Characterization of emulsions

H.-Y. Lee, M. J. McCarthy, S. R. Dungan 1998, (Experimental characterization of emulsion formation and coalescence by nuclear magnetic resonance restricted diffusion techniques), J. Am. Oil Chem. Soc. 75, 463. 

M. A. d Avila 2003, Flow and Characterization of Emulsions by Nuclear Magnetic Resonance, Ph.D. Dissertation, University of California at Davis. 

J Mikula, VA Munoz. Characterization of emulsions and suspensions in the petroleum industry using cryo-SEM and CLSM. Colloids Surfaces A Physicochem Eng Aspects, 174(1—2) 23—36, 2000. 

Armand, M., Borel, P., Dubois, C., Senft, M., Peyrot, J., Salducci, J., Lafont, H., Lairon, D. (1994). Characterization of emulsions and lipolysis of dietary lipids in the human stomach. American Journal of Physiology — Gastrointestinal and Liver Physiology, 266, G372-G381. 

The characterization of emulsions by particle size distribution analysis has been facilitated in recent years by a range of new instruments. Most of these instruments employ laser light diffraction principles, and have replaced older spectrophotometric methods. 

The next four chapters provide an introduction to the concepts and techniques needed to study and understand dispersion stability. Some approaches to the characterization of emulsions, foams and suspensions, and of their dispersed species (droplets, bubbles and particles)are described in Chapter 2. The concepts of surface tension, wettability and surface activity, which are important to the stability and properties of all types of dispersion, are described in Chapter 3. To this is added the nature of electrically charged surfaces in Chapter 4. All of these aspects are brought together in Chapter 5 in an introduction to the stability of dispersions. 

McClements, D.J. Critical review of techniques and methodologies for characterization of emulsion stability. Crit Rev Food Sci Nutri 47 (2007) 611-649. 

Another promising application of S-FFF is the characterization of emulsions and S-FFF is used as the standard technique for emulsion characterization in some laboratories [390]. Manifold emulsions or organelles have been fractionated with S-FFF [75,383,391-396] including perfluorocarbon blood substitutes [391]. 

Relating Bulk-Fat Properties to Emulsified Systems Characterization of Emulsion Destabilization by Crystallizing Fats... 

References to the characterization of emulsion polymers with IR or Raman spectroscopy are not numerous, and IR is used only in very specific cases. Only very few cases of the determination of copolymer composition with IR have been reported. An example where IR is utilized concerns the analysis of poly(methyl acrylate(MA)-co-styrene (S)) copolymers in chloroform at a concentration of 10% w/v [51]. Hergeth and Lange [52] used IR and Raman spectroscopy to study the stracture of core-shell latex particles of poly(vinyl acetate)(PVAc)-polystyrene (PS), and also obtained information about die interfacial layer between the two polymer phases. 

An experimental technique dedicated to studies of the dynamic and mechanical properties of adsorption layers at the liquid/liquid interface is described with respect to its impact on the characterization of emulsions. A recently developed oscillating-drop technique gives access to the smface rheology of adsorption layers composed of smfactants and/or proteins. The same methodology seems to be suitable for direct investigations of single emulsion-film properties for which a relevant modification of the experimental set-up is... 

The third chapter, by Wasan and Nikolov, discusses fundamental processes in emulsions, i.e., ereaming/sed-imentation, flocculation, coalescence, and final phase separation. A number of novel experimental facilities for characterization of emulsions and the above-mentioned processes are presented. This chapter highlights recent techniques such as film rheometry for dynamic film properties, capillary force balance in eonjunetion with differential microinterferometry for drainage of curved emulsion films, Kossel diffraction, imaging of interdroplet interactions, and piezo imaging spectroscopy for drop-homophase coalescence rate processes. 

Working with emulsion systems is nothing new to people in the petroleum industry. Historically and economically, the most important problems in the oil industry have been in the area of breaking up o/w emulsions formed within reservoirs. However, the breaking and formation of emulsions plays a very important role in other technological applications in the oil industries. Because of their wide-ranging practical importance, it is necessary to discuss the fundamental aspects and methods of characterization of emulsions. 

Emulsions are extracted with pentane or hexane, which separates the emulsion and, after concentrating the solution, high-temperature GC is used to identify oil and wax. The residue from the organic extraction is dried and extracted with hot water to dissolve oxidizer(s). Testing of the water extract by spot tests or IC identifies ammonium, potassium, nitrate, and perchlorate ions when potassium perchlorate is used for increased sensitivity. Identification of the emulsifying system has potential for further characterization of emulsions. The residue from the water extract is primarily aluminum... 

An Empirical Approach to Demulsifier Selection. Research into emulsion fundamentals added greatly to our understanding of the factors that determine emulsion stability and the surface-active chemicals that can be used to manipulate those factors. In spite of these advances, the requirement for blending demulsifiers in order to achieve acceptable field performance means that empirical approaches are often required for demulsifier selection. In fact, complete characterization of emulsion properties, including process residence times, temperatures, and product requirements still only provides guidance in the selection of process demulsifiers. The costs and time involved in achieving the level of characterization required for a fundamental approach can also be... 

Sobisch T, Lerche D (2005) Rapid characterization of emulsions for emulsifier selection, quality control and evaluation of stability using multisample analytical centrifugation, SCI/RSC/SCS conference on cosmetics and colloids, London, 15 Feb 2005. 

---