Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States.
Langmuir. 2013 Aug 6;29(31):9744-9. doi: 10.1021/la401172z. Epub 2013 Jul 26.
The dynamic and structural properties of a room-temperature ionic liquid (RTIL) 1-butyl-3-methyl-imidazolium(trifluoromethanesulfonimide) ([C4mim][Tf2N]) confined in silica and carbon mesopores were investigated by molecular dynamics (MD) simulations and nuclear magnetic resonance (NMR) experiments. The complex interfacial microstructures of confined [C4mim][Tf2N] are attributed to the distinctive surface features of the silica mesopore. The temperature-dependent diffusion coefficients of [C4mim][Tf2N] confined in the silica or carbon mesopore exhibit divergent behavior. The loading fraction (f = 1.0, 0.5, and 0.25) has a large effect on the magnitude of the diffusion coefficient in the silica pore and displays weaker temperature dependence as the loading fraction decreases. The diffusion coefficients of mesoporous carbon-confined [C4mim][Tf2N] are relatively insensitive to the loading faction and exhibit a temperature dependence that is similar to the bulk dependence at all loading levels. Such phenomena can be attributed to the unique surface heterogeneity, dissimilar interfacial microstructures, and interaction potential profile of RTILs near silica and carbon walls.
通过分子动力学（MD）模拟和核磁共振（NMR）实验研究了室温离子液体（RTIL）1-丁基-3-甲基-咪唑鎓（三氟甲磺酰亚胺）([C4mim][Tf2N])在二氧化硅和碳介孔中的动态和结构特性。受限 [C4mim][Tf2N] 的复杂界面微结构归因于二氧化硅介孔的独特表面特征。在二氧化硅或碳介孔中受限的 [C4mim][Tf2N] 的温度相关扩散系数表现出发散行为。负载分数 (f = 1.0、0.5 和 0.25) 对二氧化硅孔中扩散系数的大小有很大影响，并且随着负载分数的降低，其温度依赖性变弱。介孔碳限域 [C4mim][Tf2N] 的扩散系数对负载分数相对不敏感，并且在所有负载水平下都表现出与体相相似的温度依赖性。这种现象可以归因于 RTIL 在二氧化硅和碳壁附近的独特表面不均匀性、不同的界面微结构和相互作用势轮廓。
