Potentials of classical force fields for interactions between Na<sup>+</sup> and carbon nanotubes<xref rid="cpb_27_9_098801_fn1" ref-type="fn">*</xref><fn id="cpb_27_9_098801_fn1"><label>*</label><p>Project supported by the National Science Fund for Outstanding Young Scholars of China (Grant No. 11722548) and the National Natural Science Foundation of China (Grant Nos. 11574339 and 11404361).</p></fn>

Potentials of classical force fields for interactions between Na⁺ and carbon nanotubes**

Project supported by the National Science Fund for Outstanding Young Scholars of China (Grant No. 11722548) and the National Natural Science Foundation of China (Grant Nos. 11574339 and 11404361).

Li De-Yuan^{1, 2}, Shi Guo-Sheng^{1, 2, †}, Hong Feng^{1, ‡}, Fang Hai-Ping^{1, 2}

(color online) (a) Na⁺ ions move into the filter membrane consisting of four (9,9)-type CNTs and blocked the water flow at 10 ns with the cation-π interactions. (b) Na⁺ ions are still dispersed in the solution without the cation-π interactions at 10 ns. (c) Cumulative water flow with time through the CNT membrane with (red) and without (black) cation-π interactions.