Enrichment and distribution of counterions in spherical polyelectrolyte brushes probed by SAXS
Enrichment and distribution of counterions in spherical polyelectrolyte brushes probed by SAXS
复制标题
DOI：
10.1002/polb.24828
复制
发表时间：
2019-06
期刊：
影响因子：
--
通讯作者：
Zhishuang Ye;Li Li-Li;Fang Zhao;Yuchuan Tian;Yunwei Wang;Qingsong Yang;Liheng Dai;Xuhong Guo
中科院分区：
文献类型：
--
作者：
Zhishuang Ye;Li Li-Li;Fang Zhao;Yuchuan Tian;Yunwei Wang;Qingsong Yang;Liheng Dai;Xuhong Guo
采用SAXS、DLS和Zeta电势相结合的方法，研究了反离子[Li+、Na+、Rb+、Cs+、NH4+、(CH3)4N+]与球形聚电解质刷(SPBS)的空间相关性。结果表明，该电刷的SAXS强度分布对Na+浓度表现出“不敏感”。相反，在刷层中引入密度低于钠[NH4+，(CH3)4N+和Li+]的盐离子将导致散射强度的降低，而引入密度高于钠离子(Rb+和Cs+)的盐离子将导致相反的结果。SAXS、DLS和Zeta电位的综合结果证实，电刷的崩塌和电刷层中反离子的浓缩是同时发生的。实验进一步证明，电刷壳最内层的反离子浓度可比本体浓度提高数百倍，且电刷壳内的反离子分布服从径向衰减分布。SAXS被证实在探测SPB内反离子的富集度和分布方面具有很强的能力。2019威利期刊公司J.Polym。科学，B部分：多晶硅。物理学2019、57、738-747
The spatial correlation of counterions [Li+, Na+, Rb+, Cs+, NH4+, (CH3)4N+] with spherical polyelectrolyte brushes (SPBs), which consist of a PS core and chemically grafted PSS chains, was comprehensively studied through a combination of SAXS, DLS, and Zeta potential. Results show that the SAXS intensity profiles of the brush appears to be “insensitive” to the concentration of Na+. By contrast, introducing salt ions with a density lower than sodium [NH4+, (CH3)4N+and Li+] into the brush layer will cause a decrease in the scattering intensity while introducing those with a higher density than sodium (Rb+and Cs+) will cause the opposite result. As verified by the combined results of SAXS, DLS, and Zeta potential, the collapse of the brush and the enrichment of the counterions in the brush layer occur simultaneously. It was further demonstrated that the concentration of counterions enriched in the innermost layer of the brush shell can be enhanced up to hundreds of times compared with the bulk concentration, and the counterion distribution in SPB shell follows a radial attenuation distribution. SAXS is confirmed to be powerful in probing the enrichment and distribution of counterions within SPB. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys.2019,57, 738–747