title: Cloud Point and Liquid-Liquid Equilibrium Behavior of Thermosensitive Polymer L61 and Salt Aqueous Two-Phase System.
abstract: The cloud point of thermosensitive triblock polymer L61, poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO), was determined in the presence of various electrolytes (K2HPO4, (NH4)3C6H5O7, and K3C6H5O7). The cloud point of L61 was lowered by the addition of electrolytes, and the cloud point of L61 decreased linearly with increasing electrolyte concentration. The efficacy of electrolytes on reducing cloud point followed the order: K3C6H5O7 > (NH4)3C6H5O7 > K2HPO4. With the increase in salt concentration, aqueous two-phase systems exhibited a phase inversion. In addition, increasing the temperature reduced the concentration of salt needed that could promote phase inversion. The phase diagrams and liquid-liquid equilibrium data of the L61-K2HPO4/(NH4)3C6H5O7/K3C6H5O7 aqueous two-phase systems (before the phase inversion but also after phase inversion) were determined at T = (25, 30, and 35) °C. Phase diagrams of aqueous two-phase systems were fitted to a four-parameter empirical nonlinear expression. Moreover, the slopes of the tie-lines and the area of two-phase region in the diagram have a tendency to rise with increasing temperature. The capacity of different salts to induce aqueous two-phase system formation was the same order as the ability of salts to reduce the cloud point.
authors.affiliation: †School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China.
authors.forename: Wenwei
authors.initials: W
authors.lastname: Rao
authors.affiliation: †School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Wang
authors.affiliation: ‡School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, PR China.
authors.forename: Juan
authors.initials: J
authors.lastname: Han
authors.affiliation: †School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: §Zhenjiang Entry-exit Inspection Quarantine Bureau, State Key Laboratory of Food Additive and Condiment Testing, Zhenjiang, 212013, PR China.
authors.forename: Tong
authors.initials: T
authors.lastname: Chen
authors.affiliation: †School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: †School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China.
authors.forename: Liang
authors.initials: L
authors.lastname: Ni
mesh_terms: D004573:Electrolytes / Q000737:chemistry; D017711:Nonlinear Dynamics; D044367:Phase Transition; D011092:Polyethylene Glycols / Q000737:chemistry*; D011409:Propylene Glycols / Q000737:chemistry*; D012492:Salts / Q000737:chemistry*; D012996:Solutions; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D004573:Electrolytes; C116176:PEO-PPO-PEO; D011409:Propylene Glycols; D012492:Salts; D012996:Solutions; D014867:Water; D011092:Polyethylene Glycols