Wang Yali, Li Lei
Department of Chemistry and Chemical Engineering, Yulin University, Yulin, Shaanxi, P.R. China 719000.
Department of Chemical & Petroleum Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States.
Langmuir. 2020 Mar 24;36(11):2743-2756. doi: 10.1021/acs.langmuir.9b03865. Epub 2020 Mar 4.
Significant progress has been made in understanding the IL-solid interface in the past three decades, and a key finding is that ILs can form solidlike layers at the interface. It has been recognized that the electrostatic forces at the solid-IL interface and self-assembly of ILs are key enablers of the IL layering. However, regarding the layering structure of ILs, research from different laboratories is not consistent; i.e., the number of solidlike layers could range from 0 to ∼60, indicating the complexity of the underlying mechanisms and/or the existence of overlooked key parameters. In the current review, we will discuss the underlying mechanisms and key parameters governing the layering of ILs on mica, the most studied model solid. First, we will present the experimental findings from various laboratories, both consistent and contradictory ones, and summarize the current understanding of the governing mechanisms. Then, we will discuss the possible key parameters, including the structure of ILs, surface modification and contamination of mica, and cosolvent impacting the solidlike layering of ILs. Finally, we will discuss future research directions in uncovering the underlying mechanisms.
在过去三十年里，人们对离子液体-固体界面的认识取得了重大进展，一项关键发现是离子液体能够在界面处形成类固体层。人们已经认识到，固体-离子液体界面处的静电力以及离子液体的自组装是离子液体分层的关键因素。然而，关于离子液体的分层结构，不同实验室的研究结果并不一致；也就是说，类固体层的数量可以从0到约60不等，这表明其潜在机制很复杂，和/或存在被忽视的关键参数。在本综述中，我们将讨论控制离子液体在云母（研究最多的模型固体）上分层的潜在机制和关键参数。首先，我们将展示各个实验室的实验结果，包括一致的和矛盾的结果，并总结目前对控制机制的理解。然后，我们将讨论可能的关键参数，包括离子液体的结构、云母的表面改性和污染，以及影响离子液体类固体分层的助溶剂。最后，我们将讨论揭示潜在机制的未来研究方向。
