How liquids charge the superhydrophobic surfaces

• Published in: Nature communications Vol. 15; no. 1; p. 4762
• Main Authors: Jin, Yuankai, Yang, Siyan, Sun, Mingzi, Gao, Shouwei, Cheng, Yaqi, Wu, Chenyang, Xu, Zhenyu, Guo, Yunting, Xu, Wanghuai, Gao, Xuefeng, Wang, Steven, Huang, Bolong, Wang, Zuankai
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 04-06-2024; Nature Publishing Group; Nature Portfolio
• Subjects: 639/766/25; 639/766/94; Current carriers; Electrification; Electron transfer; Electrons; Humanities and Social Sciences; Hydrophobic surfaces; Hydrophobicity; Ions; Liquids; multidisciplinary; Science; Science (multidisciplinary); Surface properties; Work functions
• ISSN: 2041-1723
• DOI: 10.1038/s41467-024-49088-1

Liquid-solid contact electrification (CE) is essential to diverse applications. Exploiting its full implementation requires an in-depth understanding and fine-grained control of charge carriers (electrons and/or ions) during CE. Here, we decouple the electrons and ions during liquid-solid CE by designing binary superhydrophobic surfaces that eliminate liquid and ion residues on the surfaces and simultaneously enable us to regulate surface properties, namely work function, to control electron transfers. We find the existence of a linear relationship between the work function of superhydrophobic surfaces and the as-generated charges in liquids, implying that liquid-solid CE arises from electron transfer due to the work function difference between two contacting surfaces. We also rule out the possibility of ion transfer during CE occurring on superhydrophobic surfaces by proving the absence of ions on superhydrophobic surfaces after contact with ion-enriched acidic, alkaline, and salt liquids. Our findings stand in contrast to existing liquid-solid CE studies, and the new insights learned offer the potential to explore more applications.
Liquid-solid contact electrification is widely used in various applications, yet its mechanism remains not well understood. Jin et al. show that the effect arises from electron transfer due to the work function difference between liquids and superhydrophobic surfaces and rule out the possibility of ion transfer.