正离子型疏水改性聚氧乙烯单成相组分双水相系统的相行为

PHASE BEHAVIOR OF AQUEOUS TWO-PHASE SYSTEMS WITH ONE PHASE-FORMING COMPOSITION OF CATIONIC HYDROPHOBICALLY MODIFIED ETHYLENE OXIDE POLYMER

对正离子型疏水改性聚氧乙烯(HM-EO)单成相组分双水相系统的相行为进行了考察,并分析其电荷特性.HM-EO在水溶液中呈现两亲性,可以形成胶束,进而形成带电的胶束簇集体.通过改变溶液的pH值、盐浓度及添加带相反电荷的表面活性剂SDS,可改变胶束簇集体的带电状态,从而影响系统的相行为.增大pH值,有利于系统的分相.盐的添加也可以增大双水相两相区域,正离子影响次序为K+>Na+,负离子次序为SO42->F->Cl->Br->I-.进一步考察了HM-EO和SDS之间的相互作用,结果表明SDS能与HM-EO形成混合胶束簇集体,改变HM-EO双水相系统的带电特性.

A cationic hydrophobically modified ethylene oxide polymer （HM-EO） was used to form aqueous twophase system with only one phase-forming composition. It was found that the phase separation could be achieved under room temperature. The phase behavior and charge properties of HM-EO aqueous two-phase systems were studied systematically. The amphiphilic property of HM-EO molecule resulted in the micellization and aggregation of micelles in water. The micellar aggregates formed in the bottom phase could be charged, and the net-charge could be adjusted by the pH and conductivity of bulk solution and adding sodium dodecyl sulfate （SDS） .The increase of pH would improve the phase separation of HM-EO aqueous two-phase system. The effect of salts on the phase behavior was observed. The influence of cations varied as K^＋ 〉 Na^＋ , and that of anions as SO42^- 〉 F^- 〉 Cl^- 〉 Br^- 〉 I^- . In addition, the interaction between HM-EO polymer and anion surfactant SDS was studied. The results indicated that the addition of SDS caused the formation of mixed micellar aggregates of SDS and HM-EO which changed significantly the charge property of HM-EO aqueous two-phase systems.