Centre for Organic Electronics, The University of Newcastle, Callaghan, NSW 2308, Australia.
Phys Chem Chem Phys. 2012 Apr 21;14(15):5106-14. doi: 10.1039/c2cp23694j. Epub 2012 Jan 27.
The nanostructure of the ethanolammonium nitrate (EtAN)-air surface has been investigated using X-ray reflectometry (XRR), vibrational sum frequency spectroscopy (VSFS) and neutral impact collision ion scattering spectroscopy (NICISS). The XRR data decays more rapidly than expected for a perfectly sharp interface, indicating a diffuse electron (scattering length) density profile. Modelling of the XRR data using three different fitting routines produced consistent interfacial profiles that suggest the formation of interfacial EtAN clusters. Consistent with this, VSFS reveals that the EtAN surface is predominantly covered by -CH(2)- moieties, with the -NH(3)(+) and -OH groups of the cation buried slightly deeper in the interface. The elemental profiles determined using NICISS also show enrichment of carbon relative to nitrogen and oxygen in the outermost surface layer, which is consistent with the surface cation orientation deduced from VSFS, and with the presence of EtAN aggregates at the liquid surface.
使用掠入射 X 射线反射（XRR）、振动和频光谱（VSFS）以及中性冲击碰撞离子散射光谱（NICISS）研究了乙醇铵硝酸盐（EtAN）-空气表面的纳米结构。XRR 数据的衰减速度快于理想尖锐界面的预期，表明电子（散射长度）密度分布具有扩散性。使用三种不同的拟合程序对 XRR 数据进行建模，得到了一致的界面分布，表明界面处形成了 EtAN 团簇。这与 VSFS 的结果一致，VSFS 表明 EtAN 表面主要由 -CH(2)-部分覆盖，阳离子的 -NH(3)(+)和 -OH 基团稍微埋深在界面中。使用 NICISS 确定的元素分布也显示了最外层表面层中碳相对于氮和氧的富集，这与 VSFS 推断的表面阳离子取向一致，也与液体表面处 EtAN 聚集体的存在一致。
