Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U. K.
Henry Royce Institute, University of Manchester, Oxford Road, Manchester M13 9PL, U. K.
J Am Chem Soc. 2023 Apr 12;145(14):8007-8020. doi: 10.1021/jacs.2c13630. Epub 2023 Mar 28.
The unique layered structure of graphite with its tunable interlayer distance establishes almost ideal conditions for the accommodation of ions into its structure. The smooth and chemically inert nature of the graphite surface also means that it is an ideal substrate for electrowetting. Here, we combine these two unique properties of this material by demonstrating the significant effect of anion intercalation on the electrowetting response of graphitic surfaces in contact with concentrated aqueous and organic electrolytes as well as ionic liquids. The structural changes during intercalation/deintercalation were probed using in situ Raman spectroscopy, and the results were used to provide insights into the influence of intercalation staging on the rate and reversibility of electrowetting. We show, by tuning the size of the intercalant and the stage of intercalation, that a fully reversible electrowetting response can be attained. The approach is extended to the development of biphasic (oil/water) systems that exhibit a fully reproducible electrowetting response with a near-zero voltage threshold and unprecedented contact angle variations of more than 120° within a potential window of less than 2 V.
石墨独特的层状结构及其可调的层间距为离子进入其结构提供了几乎理想的条件。石墨表面光滑且化学惰性，这意味着它是电润湿的理想基底。在这里，我们通过展示阴离子插层对与浓水电解质和有机溶剂以及离子液体接触的石墨表面的电润湿响应的显著影响，结合了这种材料的这两个独特性质。利用原位拉曼光谱探测了插层过程中的结构变化，并利用这些结果深入了解了插层阶段对电润湿速率和可逆性的影响。通过调节插层剂的大小和插层阶段，我们证明可以获得完全可逆的电润湿响应。该方法扩展到两相（油/水）系统的开发，该系统表现出完全可重复的电润湿响应，具有近零电压阈值和前所未有的接触角变化超过 120°，在小于 2 V 的电位窗口内。
