Orientation and mutual location of ions at the surface of ionic liquids.
Orientation and mutual location of ions at the surface of ionic liquids.
复制标题
DOI：
10.1039/c0cp00683a
复制
发表时间：
2010-10
期刊：
影响因子：
--
通讯作者：
V. Lockett;R. Sedev;S. Harmer;J. Ralston;M. Horne;T. Rodopoulos
中科院分区：
文献类型：
--
作者：
V. Lockett;R. Sedev;S. Harmer;J. Ralston;M. Horne;T. Rodopoulos
用角分辨X射线光电子能谱(ARXPS)和同步辐射X射线光电子能谱(SXPS)研究了室温离子液体(ILS)中液-真空界面的结构。通过改变极角和比较所选离子液体的结果，我们确定了表面层的存在，该表层在化学上与本体不同。具体地说，这一层：(I)由阴离子和阳离子的饱和碳链中的脂肪族碳原子富集，以及(Ii)在垂直于表面的方向上包含不均匀分布的阳离子和阴离子。这种不均匀的分布产生了从表面延伸到液体的势梯度。我们明确地表明，这一层并不是由于杂质的存在。
The structure of the liquid-vacuum interface in room temperature ionic liquids (ILs) is investigated using angle-resolved X-ray photoelectron spectroscopy (ARXPS) and synchrotron X-ray photoelectron spectroscopy (SXPS). By varying the polar angle and comparing the results for the chosen ionic liquids, we identify the presence of a surface layer that is chemically different to the bulk. In particular, this layer: (i) is enriched by aliphatic carbon atoms from the saturated carbon chains of the anions and cations, and (ii) contains an unequal distribution of cations and anions in a direction normal to the surface. This unequal distribution creates a potential gradient which extends from the surface into the liquid. We show unequivocally that this layer is not due to the presence of impurities.