Browsing by Autor "J. Lachaise"

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Contribution to the modelization of the emulsification in a colloid mill
(2007) Christophe Dicharry; Bruno Mendiboure; G. Marion; J. Lachaise; Jean‐Louis Salager
We propose a stochastic model to forecast the droplet size distributions of oil in water emulsions generated in a colloid mill. The model lays on breakup sequences of the oil droplets induced by the shear field existing within the mill. One single set of the three fitting parameters is sufficient to account for the variations of the droplet size distributions in function of the surfactant concentration, the surfacant nature, the rotation speed of the rotor.
Improved determination of the initial structure of liquid foams
(2007) J. Lachaise; Smail Sahnoun; Christophe Dicharry; Bruno Mendiboure; Jean‐Louis Salager
Liquid foams are obtained by independently fixing foaming solution and gas flows through a coarse porous structure. Precise measurements of these flows immediately give the gas-volume fractions of the foams; real-time diffractometry gives their initial bubble-size distributions and these are found to be lognormal. — The proposed methods provide reproducible foams and are sensitive. They will be useful to test the interbubble gas transfer theory and to grade surfactants according to their ability to form persistent foams.
Solubilization of polar oils in microemulsion systems
(2007) M. Miñana Pérez; Jean‐Louis Salager; M. Miñana‐Pérez; Alain Graciaa; J. Lachaise
A new type of amphiphile that contains both conventional surfactant and lipophilic linker features in a single molecule was designed and tested. In these so-called extended surfactants, a polypropylene oxide chain of variable length is inserted in between the conventional polar and apolar groups. With this type of surfactant, it was possible to produce for the first time a middle phase microemulsion in alcohol-free systems with long chain (C10–C18) synthetic and natural triglyceride oils. High molecular weight hydrocarbons were solubilized as well. The reported solubilization at optimum is found to depend upon both the propylene oxide chain length and the oil structure. The solubilization parameter of polar oils is found to attain quite remarkable values, in the range of several milliliters of oil per gram of extended surfactant, an interesting feature as far as the applications are concerned.