Yao Sicheng, Zhou Shenglin, Zhang Jiapeng, Yang Zhaohui, Zhang Xiaohua
Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou, 215006, People's Republic of China.
Jiangsu Key Laboratory of Thin Films, Soochow University, Suzhou, 215006, People's Republic of China.
Nanotechnology. 2021 Mar 5;32(10):105709. doi: 10.1088/1361-6528/abcf6f.
We investigated the effect of an electric treatment on the wettability of aqueous solution on carbon nanotubes (CNT) and ion transport behaviors in superhydrophobic porous carbon nanotube sponges (CNTS). This electric activation treatment where an electric voltage was applied across highly porous CNT sponge induced an electrowetting effect. This effect significantly reduced interfacial tensions between CNT sidewalls and aqueous liquids. Meanwhile, polar functional groups were also introduced on CNTs. Both electrowetting effect and polar functional groups greatly improved the wettability of aqueous solutions on CNT sidewalls. After the electric treatment, we observed a dramatic increase in the overall rate of ion flow across porous CNT sponges. The formation of solution channels during the electric treatment is responsible for the enhanced ionic transport in porous CNT sponges. The overall rate of ion flow increased with the increases in electric treatment time and voltage. The crucial role of electric treatment parameters in the ion transport provides a new strategy for precisely controlling the ion transport across CNT sponges by tuning electric treatment time or voltage. Importantly, the good wettability of aqueous solution on CNT sidewalls greatly increased the effective surface area of CNT sponges and thus significantly improved the performance of CNTS-based supercapacitors after the electric treatment.
我们研究了电处理对水溶液在碳纳米管（CNT）上的润湿性以及超疏水多孔碳纳米管海绵（CNTS）中离子传输行为的影响。这种在高度多孔的CNT海绵上施加电压的电活化处理会引发电润湿效应。该效应显著降低了CNT侧壁与水性液体之间的界面张力。同时，碳纳米管上也引入了极性官能团。电润湿效应和极性官能团都极大地改善了水溶液在CNT侧壁上的润湿性。电处理后，我们观察到跨多孔CNT海绵的离子流动总速率显著增加。电处理过程中溶液通道的形成是多孔CNT海绵中离子传输增强的原因。离子流动总速率随电处理时间和电压的增加而增加。电处理参数在离子传输中的关键作用为通过调节电处理时间或电压精确控制跨CNT海绵的离子传输提供了一种新策略。重要的是，水溶液在CNT侧壁上的良好润湿性大大增加了CNT海绵的有效表面积，从而在电处理后显著提高了基于CNTS的超级电容器的性能。
