Hofmeister Salt Effects on the LCST Behavior of Poly(2-Oxazoline) Star Ionomers

被引：21

作者：

ten Brummelhuis, Niels ^{[1
]}

Secker, Christian ^{[1
]}

Schlaad, Helmut ^{[1
]}

机构：

[1] Max Planck Inst Colloids & Interfaces, Dept Colloid Chem, D-14424 Potsdam, Germany

来源：

MACROMOLECULAR RAPID COMMUNICATIONS | 2012年 / 33卷 / 19期

关键词：

block copolymers; Hofmeister salts; poly(2-oxazoline); star polymers; thermoresponsive; SERIES; POLYMERS; WATER; MACROMOLECULES; PNIPAM;

D O I：

10.1002/marc.201200406

中图分类号：

O63 [高分子化学（高聚物）];

学科分类号：

070305 ; 080501 ; 081704 ;

摘要：

Effects of pH, ionic strength, and type of salt (variation of anions) on the cloud-point temperature (TCP) of thermoresponsive poly(2-ethyl-2-oxazoline) star ionomers are investigated. TCPs can be varied in a wide range, from 10 to >95 degrees C, corresponding with the Hofmeister series and the ionization of the core. Addition of salt weakens the influence of pH. For star copolymer with an amine core similar trends are observed as for star copolymers with a carboxylic acid core, although the presence of a chaotropic salt affords an inversion of the effect of pH, that is, TCPs are lowest at pH 3, where the amine groups are fully protonated. This effect is likely due to the specific binding of chaotropic anions to the amine and ammonium groups, which is not observed for carboxylic acid groups.

引用

页码：1690 / 1694

页数：5

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