Au(111)/咪唑基离子液体界面结构研究：阳离子侧链长度的影响

本文结合电化学方法与原子力显微镜力曲线技术，研究了两种烷基侧链长度不同的离子液体BMITFSA和OMITFSA在Au(111)电极表面附近的层状结构的数目和耐受力对电位的依赖性，探究了烷基侧链长度变化对界面层状结构的影响. 研究表明，不同烷基侧链长度的离子液体体系力-电位曲线形状基本相似. 在零电荷电位（the potential of zero charge，PZC）附近时，力值最小，因为此时电极表面荷电量较小，层状结构不稳定；电位偏离PZC的过程中，第一层层状结构力值呈现先增大后减小的趋势. 受到烷基侧链所处的不同位置影响，在PZC电位以负，短侧链离子液体的层状结构稳定性较好，而PZC电位以正，长侧链离子液体的稳定性较好.

An Investigation on the Structure of Au(111)/Imidazolium-Based Ionic Liquid Interface: Effect of Alkyl Side Chain Length

In this work, we comparatively investigated the interfacial structures at Au(111) electrode surfaces in two ionic liquids (ILs) with different alkyl chain lengths by combining AFM force curve technique and electrochemical methods. The number and stability of the layering structures, and their potential-dependency were analyzed. The experimental results indicated that the tendencies of force-potential curves in the two ILs behave the same way. At potentials close to PZC, the ions arrange loosely, which lowers the stability of the layering structure. As the potential shifting away from PZC, more ions attach to electrode surface, which increases the stability of layering structure, while further increase of the ions will weaken the stability because of the lattice saturation of ions. However, the location of the alkyl chain at potentials negative to the PZC differs from that at potentials positive to the PZC, leading to an adverse effect on the stability at negatively charged surface and a synergistic effect on the stability at positively charged surface, respectively.