Small-angle scattering study of perfluorosulfonated ionomer solutions
Small-angle scattering study of perfluorosulfonated ionomer solutions
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DOI：
10.1021/jp9623047
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发表时间：
1997-03-06
影响因子：
3.3
通讯作者：
Williams, CE
中科院分区：
文献类型：
--
作者：
Loppinet, B;Gebel, G;Williams, CE
用小角X射线和中子散射研究了全氟磺化离聚体(PFSI)在醇、酰胺和水等极性溶剂中的结构。对比度变化法表明，离聚体分子粒子形成等散射长度的致密粒子。对稀溶液的研究使人们能够证明PFSI溶液的棒状结构。圆柱形粒子的半径由散射曲线的形状和强度确定。通过对散射曲线的大角度渐近行为的分析，证实了这些结果。半径的典型值被发现在20埃左右。棒的直径与聚合物-溶剂的界面能有关，而溶剂的介电常数只对局部有序起作用。用混合溶剂考察了结构随溶剂的变化，并研究了反离子的影响。加盐对小角散射谱的影响可以解释为由于干扰项的消失而导致局域有序度的降低，而粒子的形状没有改变。
A structural study of perfluorosulfonated ionomer (PFSI) solutions in polar solvents such as alcohols, amides, and water using both small-angle X-ray and neutron scattering is presented. Contrast variation methods have shown that the ionomer molecule particles form dense particles of constant scattering length. The study of dilute solutions allows one to evidence the rodlike structure of PFSI solutions. The radius of the cylindrical particles is determined from both the shape and the intensities of the scattering curves. These results are confirmed by the analysis of the asymptotic behavior at large angles of the scattering curves. Typical values for the radii are found to be around 20 Angstrom. The diameter of the rod is shown to be related to the polymer-solvent interfacial energy, whereas the dielectric constant of the solvent acts only on the local order. Mixtures of solvents have been used to check the evolution of the structure with the solvents, The effect of the counterion is also studied. The effect of added salt on the small-angle scattering spectra can be interpreted as due to a decrease of the local order through the disappearance of the interference term and the shape of the particles is not modified.