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Phase Diagrams of the Aqueous Two-Phase Systems of Poly(ethylene glycol)/Sodium Polyacrylate/Salts
Department of Biochemistry and Structural Biology, University of Lund, P.O. Box 124, SE-221 00 Lund, Sweden
Department of Physics, IBILCE/UNESP, São Paulo State University, Rua Cristovão Colombo, 2265, SP, CEP 15054-000, São Jose do Rio Preto, Brazil
Department of Biochemical and Pharmaceutical Technology, University of São Paulo, Av. Prof. Lineu Prestes, 580—Bloco 16, Cidade Universitaria, CEP 05508-000, São Paulo, Brazil
* Author to whom correspondence should be addressed.
Received: 15 February 2011; Accepted: 7 March 2011 / Published: 9 March 2011
Abstract: Aqueous two-phase systems consisting of polyethylene glycol (PEG), sodium polyacrylate (NaPAA), and a salt have been studied. The effects of the polymer size, salt type (NaCl, Na2SO4, sodium adipate and sodium azelate) and salt concentrations on the position of the binodal curve were investigated. The investigated PEG molecules had a molar mass of 2,000 to 8,000 g/mol, while that of NaPAA was 8,000 g/mol. Experimental phase diagrams, and tie lines and calculated phase diagrams, based on Flory-Huggins theory of polymer solutions are presented. Due to strong enthalpic and entropic balancing forces, the hydrophobicity of the added salt has a strong influence on the position of the binodal, which could be reproduced by model calculations.
Keywords: poly(ethylene glycol); sodium polyacrylate; ATPS; Flory-Huggins theory; phase diagram; hydrophobic ions
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Johansson, H.-O.; Feitosa, E.; Junior, A.P. Phase Diagrams of the Aqueous Two-Phase Systems of Poly(ethylene glycol)/Sodium Polyacrylate/Salts. Polymers 2011, 3, 587-601.
Johansson H-O, Feitosa E, Junior AP. Phase Diagrams of the Aqueous Two-Phase Systems of Poly(ethylene glycol)/Sodium Polyacrylate/Salts. Polymers. 2011; 3(1):587-601.
Johansson, Hans-Olof; Feitosa, Eloi; Junior, Adalberto Pessoa. 2011. "Phase Diagrams of the Aqueous Two-Phase Systems of Poly(ethylene glycol)/Sodium Polyacrylate/Salts." Polymers 3, no. 1: 587-601.