Cationic and anionic poly(N-isopropylacrylamide) based submicron gel particles:: Electrokinetic properties and colloidal stability
Cationic and anionic poly(N-isopropylacrylamide) based submicron gel particles:: Electrokinetic properties and colloidal stability
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DOI：
10.1021/jp0540508
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发表时间：
2006-03-16
影响因子：
3.3
通讯作者：
Elaïssari, A
中科院分区：
文献类型：
--
作者：
López-León, T;Ortega-Vinuesa, JL;Elaïssari, A
采用间歇自由基聚合法合成了阳离子和阴离子型聚N-异丙基丙烯酰胺（NIPAM）微凝胶乳液。研究了这两种样品的流体力学性质、胶体稳定性和动电特性。通过考虑盐度和温度对热敏聚合物微区收缩的影响，讨论了流体动力学颗粒尺寸的变化。胶体的稳定性也依赖于温度和电解质浓度。得到了具有两个明确定义的区域（稳定和不稳定）的稳定图。从一个域到另一个域的流动是完全可逆的，这是由于聚合物特有的水化（脱水）特性。的电动行为，这取决于电和摩擦性能的颗粒，通过电泳迁移率测量进行了分析。结果进行了讨论，考虑颗粒结构对温度和盐度的依赖性，和双电层压缩。此外，电泳迁移率数据进行了分析，使用Ohshima的方程覆盖的离子可渗透的表面带电层的颗粒，以及使用另一个更简单的方程位于一个流体动力学等效硬球的电荷。这两种胶乳的性质之间的差异是合理的存在下的亲水性共聚单体，甲基丙烯酸氨乙酯盐酸盐（AEMH），在阳离子微凝胶。
A cationic and an anionic poly(N-isopropylacrylamide) (poly(NIPAM)) microgel latex were synthesized via batch radical polymerization under emulsifier-free conditions. The hydrodynamic properties, colloidal stability, and electrokinetic characteristics of these two samples were studied. The hydrodynamic particle size variation was discussed by considering the effect of salinity and temperature on the shrinkage of the thermally sensitive polymer domains. The colloidal stability also depended on temperature and electrolyte concentration. A stability diagram with two well-defined domains (stable and unstable) was obtained. The flow from one domain to the other was fully reversible due to the peculiar (de)hydration properties of the polymer. The electrokinetic behavior, which depends on electrical and frictional properties of the particles, was analyzed via electrophoretic mobility measurements. Results were discussed by considering both the particle structure dependence on temperature and salinity, and the electric double layer compression. In addition, the electrophoretic mobility data were analyzed using Ohshima's equations for particles covered by an ion-penetrable surface charged layer, as well as using another simpler equation for charges located on a hydrodynamic equivalent hard sphere. Differences between the properties of both latexes were justified by the presence of a hydrophilic comonomer, aminoethyl methacrylate hydrochloride (AEMH), in the cationic microgel.