Department of Chemical Engineering, College of Engineering, Kyung Hee University, 1 Seochon-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, Korea.
J Phys Chem B. 2011 Mar 3;115(8):1743-50. doi: 10.1021/jp1062176. Epub 2011 Feb 3.
We demonstrated thermal transitions and physical gelation of binary ionic salts through interionic interactions, which consist of pyrrolidinium-N-propanesulfonate zwitterionic compound (PyrZIC) and lithium bis(trifluorosulfonyl)imide (LiTFSI). The transition behaviors of binary ionic gels were attributed to conformational changes in the cations and anions of PyrZIC and LiTFSI as analyzed by density functional theory (DFT), principal component analysis (PCA), and two-dimensional infrared correlation spectroscopy (2D IR COS). Furthermore, the geometries of binary PyrZIC-LiTFSI systems were strongly influenced by the electrostatic interactions between two ionic salts. The different dynamic processes in the PyrZIC- and LiTFSI-rich phases, which are classified by the transition point of PCA plots, were induced by the conformational changes in the respective interaction fields, as shown by 2D correlation spectra. In particular, LiTFSI-rich binary gels revealed characteristic four-leaf-clover and butterfly patterns under their unique chemical circumstances, which were different from those of PyrZIC-rich gels. Consequently, these computational and experimental investigations provide an analytical tool to understand the physical phenomenon and interactions occurring in the unveiled and complicated systems.
我们通过离子间相互作用展示了二元离子盐的热转变和物理凝胶化，这些相互作用由吡咯烷-N-丙磺酸内盐（PyrZIC）和双（三氟甲烷磺酰基）亚胺锂（LiTFSI）组成。通过密度泛函理论（DFT）、主成分分析（PCA）和二维红外相关光谱（2D IR COS）分析，二元离子凝胶的转变行为归因于 PyrZIC 和 LiTFSI 的阳离子和阴离子的构象变化。此外，二元 PyrZIC-LiTFSI 系统的几何形状受到两种离子盐之间静电相互作用的强烈影响。在 PCA 图的转折点分类的 PyrZIC 和 LiTFSI 丰富相中的不同动态过程，是由各自相互作用场中的构象变化引起的，如二维相关光谱所示。特别是，LiTFSI 丰富的二元凝胶在其独特的化学环境下显示出特征的四叶苜蓿和蝴蝶图案，与 PyrZIC 丰富的凝胶不同。因此，这些计算和实验研究为理解未揭示和复杂系统中发生的物理现象和相互作用提供了分析工具。
