Characterization of chain conformations in perfluorosulfonic acid membranes using electron energy loss spectroscopy
Characterization of chain conformations in perfluorosulfonic acid membranes using electron energy loss spectroscopy
复制标题
使用电子能量损失谱表征全氟磺酸膜中的链构象
DOI：
10.1039/c4ra10012c
复制
发表时间：
2015
期刊：
影响因子：
3.9
通讯作者：
S. Paddison
中科院分区：
文献类型：
--
作者：
Chen Wang;G. Duscher;S. Paddison
全氟磺酸（PFSA）离聚物的链构象：在配备有单色器的200 kV透射电子显微镜（TEM）上用电子能量损失谱（EELS）研究NafionTM和Aquivion®。与聚四氟乙烯（PTFE）的结果进行了比较，以评估的全氟醚侧链的离聚物上的PTFE主链的结构的影响。在低损失区和碳K边的精细结构中确定了对应于构象变化的几个独特的光谱特征。从高层次的密度泛函理论（DFT）为基础的电子结构计算得到的结果证实了PFSA离聚物的EEL光谱的构象依赖性。与从实验中获得的光谱的比较揭示了特定的侧链化学和骨架构象之间的相关性。这种光谱信息将使我们能够进一步探索这些材料的形态学特性时，结合额外的成像技术。
Chain conformations of the perfluorosulfonic acid (PFSA) ionomers: Nafion™ and Aquivion® were investigated with electron energy-loss spectroscopy (EELS) on a 200 kV transmission electron microscope (TEM) equipped with a monochromator. The results were compared with polytetrafluoroethylene (PTFE) to evaluate the effect of the pendant perfluoroether side chains of the ionomers on the structure of the PTFE backbone. Several unique spectroscopic features corresponding to conformational changes were identified in the low-loss region and the fine structures of the carbon K-edge. Results obtained from high-level density function theory (DFT) based electronic structure calculations confirmed the conformational dependence of the EEL spectra of the PFSA ionomers. Comparison with the spectra obtained from the experiments revealed the correlation between the specific side chain chemistry and backbone conformation. This spectroscopic information will allow us to further explore the morphological properties of these materials when combining with additional imaging techniques.