Emulsions droplet size

Much commercial equipment is available for emulsification (Fig. 3) and has been well described (9). The following discusses the relations between energy input and emulsion droplet size. 

The responses chosen all relate to important foam properties. We believed that yi, the emulsion droplet size, determines y2, the cell size in the resultant foam, and we wished to determine whether this is true over this range of formulations. The foam pore size ys should determine the wetting rate y7, so these responses could be correlated, and yg, the BET surface area, should be related to these as well. The density y and density uniformity ys are critical to target performance as described above, and ys, the compressive modulus, is an important measure of the mechanical properties of the foam. 

K. G. Hollingsworth, M. L. Johns 2003, (Measurement of emulsion droplet sizes using PFG NMR and regularization methods),/. Colloid Interface Sci. 258, 383. 

Very finely disperse solids, which are adsorbed at the liquid/liquid interfaces, forming films of particles around the disperse globules. Certain powders can very effectively stabilize against coalescence. The solid s particle size must be very small compared with the emulsion droplet size and must exhibit an appropriate angle of contact at the three-phase (oil/water/solid) boundary [141]. 

Izquierdo, P., Wiechers, J.W., Escribano, E., Garcia-Celma, M.J., Tadros, T.F., Esquena, J., Federen, J.C. and Solans, C. (2007) A study on the influence of emulsion droplet size on the skin penetration of tetracaine. Skin Pharmacology and Physiology, 20, 263—270. 

Above 30 surfactant the MEDD apparently reached a minimum value of 1-2 pm. This third region was a function of the lower detection limit of the apparatus. Table II shows that the proportion of emulsion droplets below 3 and 1 um increased as the surfactant concentration Increased. The data emphasize the marked reduction in emulsion droplet size which occurred above 30 w/w surfactant. 

Figure 1. Effect of Binary Mixture Surfactant Concentration and Self-Emulsification Temperature on Emulsion Droplet Size for the Miglyol 812-Tagat TO System as Determined by Laser Diffraction. Bars Represent Standard Errors.

Emulsion droplet size and composition determined particle sizes and compositions. The amorphous powders (spherical with diameters less than I pm) became crystalline upon calcination... 

D3.3 Emulsion Droplet Size Determination Basic Protocol 1 Laser Diffraction Determination of Droplet Size D3.3.1... 

Electrical pulse counting, emulsion droplet size determination, 581, 583-584, 586-588... 

Ultrasonic methods infrared scanning for emulsion stability determination, 597-598 spectrometry, emulsion droplet size determination, 581 velocimetry, to measure fat, 572 Ultraviolet (UV). see also Spectrophotometry protein analysis, CD, 219-243 protein concentrations by... 

Tarr, B.D., and S.H. Yalkowsky. 1989. Enhanced intestinal absorption of cyclosporine in rats through the reduction of emulsion droplet size. Pharm Res 6 40. 

Microemulsions represent an intermediate state between micelles and ordinary emulsions, and it is a debatable issue whether or not they should be considered as swollen micelles rather than as small-droplet emulsions. Droplet size, though small, is nonetheless large enough to justify classification as emulsions. On the other hand, the observed thermodynamic stability and reproducibility is uncharacteristic of ordinary emulsions. 

Figure 1.5 shows an example of an aqueous foam with emulsified and imbibed crude oil droplets residing in its plateau borders. Using a simple model the degree of emulsification and imbibition has been found to correlate quite well with foam sensitivity to oil for a wide variety of foams, oils, and conditions [114]. A limitation of emulsification/imbibition models is that they will only be important for foam lamellae that are thick enough to accommodate realistic emulsion droplet sizes. Typical foam lamellae in porous media appear to have thicknesses on the order of tens of nm [70,71,114,328],... 

Several practical formulae have been developed for estimating the effect on emulsion viscosity of changes in key variables such as temperature, water content, and droplet size distribution, in which adjusting factors for each property are obtained from empirical correlations. An illustration is provided by Rimmer et al. [763]. Such formulae may also contain a term representing changes in emulsion droplet size due to droplet coalescence that occurs with time as the emulsion moves through the pipeline ( ageing ). 

Dickinson, E., Galazka, V. B., and Anderson, D. M. W. (1991a). Emulsifying behavior of gum arabic. Part I. Effect of the nature of the oil phase on the emulsion droplet-size distribution. Carbohydr. Polym. 14 373-383 Part II. Effect of the gum molecular weight on the emulsion droplet-size distribution. Carbohydr. Polym. 14 385-392. 

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