关键词: 离子液体, 电化学界面, 原子力显微术, 力曲线

Abstract: 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.

Key words: ionic liquids, electrochemical interface, atomic force microscopy, force curve