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arXiv · 2004.02148

Enhanced contact angle hysteresis of salt aqueous solution on graphite surface by a tiny amount of cation

Haijun Yang·Yangjie Wang·Yingying Huang·Shuai Wang·Qiufeng Lü·Xiaoling Lei·Haiping Fang
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Abstract

We experimentally observed the enhanced contact angle hysteresis (CAH) of dilute aqueous salt solution on graphite surface, i.e., 40.6$^\circ$, 34.6$^\circ$, and 27.8$^\circ$, for LiCl, NaCl, and KCl, indicating the effective tuning of the CAHs by cations. Molecular dynamics simulations reveal that the preferential adsorption of cations on the HOPG surface due to the cation-{\pi} interaction pins the water at the backward liquid-gas-solid interfaces, reducing the receding contact angle and hence enhancing the CAH. This finding provides a simple method to control the contact angle and the CAH of aqueous drops on graphitic surfaces such as graphene, carbon nanotube, biomolecules, and airborne pollutants.

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Haijun Yang, Yangjie Wang, Yingying Huang, Shuai Wang, Qiufeng Lü, Xiaoling Lei, Haiping Fang. 2020-04-05. Enhanced contact angle hysteresis of salt aqueous solution on graphite surface by a tiny amount of cation. https://arxiv.org/abs/2004.02148

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