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Characterisation of two-aqueous phase system containing a nonionic surfactant

Canselier, Jean-Paul and Gourdon, Christophe and Teixeira da Silva De La Salles, K. Characterisation of two-aqueous phase system containing a nonionic surfactant. (2005) Journal of Dispersion Science and Technology, Vol.26 (n°3). pp.303-313. ISSN 0193-2691

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Official URL: http://dx.doi.org/10.1081/DIS-200049584

Abstract

A surfactant-containing two-aqueous phase system is composed of a coacervate (surfactant-rich) phase and a dilute one (surfactant-poor). This work aims at characterizing such a two-phase system by using a recently developed optical analyzer: Turbiscan LAb expert®. This optical device allows to investigate the behavior of concentrated dispersed media through light transmission or back-scattering measurements at constant temperature. Above the cloud point of the Triton X114 solution, two distinct phenomena were observed and followed as a function of time: phase separation, with interface formation, and phase clarification, during which very small drops of one phase join the other after the interface has appeared. The process of phase separation, rather fast, appears to be composed of three steps: i) induction period with no distinct phases; ii) rapid migration of droplets and interface appearance; iii) slow displacement of the interface up to its equilibrium position. As regards clarification, the Turbiscan diagrams reveal different behaviors according to the proximity of the cloud point (Tc). About 5°C above Tc, the lighter (dilute) phase begins to clarify as the interface appears, the coacervate remaining turbid. In fact, the time required for complete phase clarification, i.e. corresponding to maximum (equilibrium) transmission intensity value, is 10-18 hrs. 10°C above the cloud point, the two phases do not reach equilibrium after 2 days. The coacervate phase then shows an oscillatory behavior with a characteristic period of ca. 25 hrs. At higher temperatures, i.e. farther from the critical point, a chaotic behavior can be observed.

Item Type:Article
Additional Information:This article is available in : http://www.informaworld.com/smpp/content~db=all~content=a713730826
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution: Université de Toulouse > Institut National Polytechnique de Toulouse - INPT
Université de Toulouse > Université Paul Sabatier-Toulouse III - UPS
French research institutions > Centre National de la Recherche Scientifique - CNRS
Laboratory name:
Laboratoire de Génie Chimique - LGC (Toulouse, France) - Réaction, mélange & séparation (RMS)
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Deposited By: Guylène Abadie

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