Entrainment swelling

Different methods [120] such as volume variation, internal phase droplet size variation, viscosity variation, density variation, tracer method, Karl-Fischer method, and electrical conductivity have been employed in the measurement of emulsion swelling. The data obtained tends to be as varied as the methods used [120]. One major drawback is that none of the above methods is capable of determining both emulsion swelling and membrane breakage in the same experiment. Further, osmotic swelling cannot be differentiated from entrainment swelling. 

Zihao W, Yuanli J, and Jufu F. The entrainment swelling of emulsion during lactic acid extraction by LSMs. J Membr Sci 1996 109 25-34. 

The mechanism of action by which silane and siloxanes reduce expansion has been attributed to water repellence and air entrainment. Phosphate addition or coatings may interfere with the dissolution of silica gel and the formation of gel. It is also possible that phosphate reduces the osmotic potential and the swelling pressure in the gel. The manner in which air entrainment reduced expansion was attributed to the accommodation of alkali-silica gel in the air void system. For example, it was found that air-entrained concrete with 4% air voids could reduce AAR expansion by 40% [23]. 

Volume Ratio of the Oil (Membrane) Phase to the Internal Phase This parameter can affect the surfactant concentration at the interface of the membrane/aqueous phases and in the bulk membrane phase, affecting emulsion swelling [120]. Both entrainment and osmotic swelling increase with increasing volume ratio of the oil (membrane) phase to the internal phase. The effect of this parameter is also dependent on the surfactant present [120]. 

An alternative means of producing actuation in a polymer is to employ ions that are mobile within the polymer phase. An applied field drives the motion of these ions and entrained solvent, leading to swelling or contraction when the ions enter or... 

Ideally, if the layer formed by particles is stable, the signal coming from the solid can be subtracted from the final spectra, and the presence of these bands does not hamper the detection and interpretation of bands from adsorbed sp>edes. However, in practice subtraction is often difficult due to the evolution of the signal of the solid with time or solution composition. Phenomena such as re-entrainment of particles by flowing solution, or swelling/ shrinkage due to the change in surface potential can explain this problem. 

The reactions between the alkaline solution and reservoir oil generate the complex oil recovery mechanisms of AF postulated to date (1) in-situ surfactant generation by neutralization (saponification), (2) reduction of the interfacial tension (IFT) at the oil-water interface, (3) temporary wettability alteration, (4) emulsification with entrainment, (5) emulsification with entrapment, (6) emulsification with coalescence, (7) oil phase swelling, and (8) breaking out the rigid films. Thus, the consumption of alkalinity through the reactions of alkaline solution with reservoir waters and rock constituents has been accepted as the most important disadvantage of the AF process. ... 

Sumathipala, K., J. E. S. Venart, and E. R. Steward. 1990. Two-Phase Swelling and Entrainment during Pressure Relief Valve Discharge, Journal of Hazardous Materials, vol. 25, pp. 219-236. 

These have the advantage of high membrane flux, which results from the very small thickness of the organic membrane. However, there are a number of operational difficulties. The first of these concerns the osmotic transport of water across the membrane as a result of different ionic concentrations in the two aqueous phases. This causes the membrane drops to swell and ultimately to break down, mixing the strip and feed solutions. Another difficulty arises with the ultimate breaking of the emulsion and separation of the two phases that can give rise to entrainment problems. In addition, the overall process is much more complex than that of the supported liquid membrane. 

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