Compositional ripening

R.A. Arlauskas and J.G. Weers Sedimentation Eield Elow Eractionation Studies of Composition Ripening in Emulsions. Langmuir 12, 1923 (1996). 

K. Pays Double Emulsions Coalescence and Compositional Ripening. Ph.D thesis, Bordeaux I University (2000). 

Under osmotic pressure gradients between the two aqueous phases of W/OAV emulsions, water may migrate either from the internal to the external phase or vice versa, depending on the direction of the osmotic pressure gradient. This process is entropically driven and is another manifestation of compositional ripening. Such... 

Pena, A.A. and Miller, C.A., Kinetics of compositional ripening in emulsions stabilized by nonionic surfactants, J. Colloid Interface ScL, 244, 154, 2001. 

The mean diameter of the droplets and its evolution versus time due to coalescence, and Ostwald and composition ripening. 

PEPTIDES / Stability of starter enzymes Cheese composition Ripening temperature... 

The thermodynamic and physical concepts explained above can help in solving phase transition problems as well as mass transfer or composition ripening in different kinds of emulsions. 

Another interesting phenomenon that can be studied by calorimetry is so-called composition ripening. In that case, an 0/W emulsion can be formed in which the dispersed medium is characterized by droplets of two different oils in a common aqueous solvent. The mixed solution is prepared by blending two different 0/W simple emulsions of well-known compositions. An instability is then created in the emulsion, due to the difference in the nature of the drops. The oils will tend to diffuse through the water medium from one drop to another, finally forming mixed droplets of the same composition. 

Numerous techniques allow qualitative information to be obtained about phenomena such as droplet composition or composition ripening. However, most of them have to be used in very dilute conditions, far from real application conditions. We have shown that calorimetry is a powerful tool for the study of those systems because it does not require dilution and the results obtained give quantitative information. Therefore, it appears to be one of the most efficient techniques for studying phenomena within emulsions, such as composition ripening and phase transitions. 

Recently, Kabalnov and Weers have suggested that micelles may simply compress the diffusion path in a manner analogous to the effect of electrolytes in compressing the electrical double layer. This will be discussed in more detail in the section on composition ripening. 

In the same study, Arlauskas and Weers examined composition ripening for several pairs of oils. The characteristic time, Tcr, for molecular diffusion between emulsions can be estimated by ... 

The initial rate of composition ripening. A, was derived by Taisne et al.f viz ... 

The composition of emulsion droplets during composition ripening processes has also been determined by changes in the crystallization temperatures of the oils... 

Table 9.4 Characteristic times for composition ripening, Tcr> Ostwald ripening, Tor, in hydrocarbon-in-water emulsions stabilized by 0.1 MSDS ...

Use of Composition Ripening to Produce Large Monodisperse Latex Particles... 

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