Effects of Hofmeister Anions on the Aggregation Behavior of PEO-PPO-PEO Triblock Copolymers
Effects of Hofmeister Anions on the Aggregation Behavior of PEO-PPO-PEO Triblock Copolymers
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DOI：
10.1021/la201463g
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发表时间：
2011-08-02
期刊：
影响因子：
3.9
通讯作者：
Zhang, Yanjie
中科院分区：
文献类型：
--
作者：
Deyerle, Branden A.;Zhang, Yanjie
采用自动熔点测定系统研究了一系列Hofmeister阴离子对聚环氧乙烷-b-聚环氧丙烷-b-聚环氧乙烷（PEO-PPO-PEO）三嵌段共聚物相行为的影响。水化程度高的阴离子和水化程度低的阴离子与聚合物的相互作用不同，并进一步影响聚合物的相转变。水化差的阴离子通过改变聚合物/水界面的界面张力和通过离子结合增强聚合物的水化来起作用。聚合物在水合阴离子存在下的相变与阴离子的水合熵直接相关。因此，该聚合物显示出两步相变在含有不良水合阴离子的溶液中，而显示出一个单步相变的存在下，以及水合阴离子。讨论了离子与聚合物相互作用，进而调控聚合物相行为的机理。
The effects of a series of Hofmeister anions on the phase behaviors of a poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer were investigated with an automated melting point system. Well hydrated anions and poorly hydrated anions interacted with the polymer differently and further affected the phase transition of the polymer. Poorly hydrated anions worked through changing the interfacial tension at the polymer/aqueous interface and in enhancing the polymer hydration by ion binding. The phase transition of the polymer in the presence of well hydrated anions correlated directly to the hydration entropy of the anions. As a consequence, the polymer showed a two-step phase transition in solutions containing poorly hydrated anions while displayed a single-step phase transition in the presence of well hydrated anions. The mechanisms of how ions interact with the polymer and further modulate its phase behaviors were discussed.