Calorimetric Investigation of the Formation of Aqueous Two-Phase Systems in Ternary Mixtures of Water, Poly(ethylene oxide) and Electrolytes (Or Dextran)

• DOI: 10.1021/jp000719t
• Publication Date: 2002-07-26T06:04:16Z
• Authors: Luís H. M. da Silva; Watson Loh
• Keywords: Ternary numeral system

The evolution of ternary mixtures containing water, poly(ethylene oxide) (PEO) and dextran or electrolytes (NaCl, Na2SO4 Li2SO4), toward the formation aqueous two-phase systems was investigated by calorimetry measuring enthalpies solution for one components in water an other component. These values were then analyzed as transfer from to second component, probe energy balance solvation transferred component between both states. obtained results confirmed that enthalpic contributions are relevant biphase presence electrolytes, but much less important two polymers. In all cases, phase separation accompanied enthalpy increase, indicating entropy increase is driving force formation. Moreover, based on data, it possible assign different behavior capable inducing (lithium sodium sulfates), chloride, which does not induce separation. A model proposed account processes leading terms electrolyte polymer interaction.