Structure and Dynamics of Loosely Cross-Linked Ionic Microgel Dispersions in the Fluid Regime
Structure and Dynamics of Loosely Cross-Linked Ionic Microgel Dispersions in the Fluid Regime
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DOI：
10.1103/physrevlett.109.048302
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发表时间：
2012-07-26
影响因子：
8.6
通讯作者：
Heinen, M.
中科院分区：
文献类型：
--
作者：
Holmqvist, P.;Mohanty, P. S.;Heinen, M.
我们报告了一个全面的实验和理论研究的温度和浓度依赖性的溶胀行为的弱交联的PNiPAm离子微凝胶颗粒在去离子流体相。当分散体从塌陷状态冷却至较低温度时，颗粒可逆地溶胀。虽然塌陷状态显示出对微凝胶数密度没有依赖性，但在较低的T下的溶胀在较低的浓度下更明显。静态对相关性和短时间的扩散函数，和浓度和温度的依赖性的微凝胶半径和有效电荷，研究使用静态和动态光散射结合国家的最先进的分析理论方案的基础上Yukawa型有效对电位和核壳模型。我们表明，只有这样一个组合，同时适合的静态和动态散射功能允许一个明确的确定的微凝胶半径和有效电荷。
We report a comprehensive experimental-theoretical study of the temperature-and concentration-dependent swelling behavior of weakly cross-linked PNiPAm ionic microgel particles in the deionized fluid phase. The particles swell reversibly when the dispersion is cooled from the collapsed state to lower temperatures. While the collapsed state shows no dependence on the microgel number density, the swelling at lower T is more pronounced at lower concentrations. The static pair correlations and short-time diffusion functions, and the concentration and temperature dependence of the microgel radius and effective charge, are studied using static and dynamic light scattering in combination with state-of-the-art analytical theoretical schemes based on a Yukawa-type effective pair potential and a core-shell model. We show that only such a combined, simultaneous fit of static and dynamic scattering functions allows for an unambiguous determination of the microgel radius and effective charge.