Journal of Bionic Engineering (2024) 21:1347–1359 https://doi.org/10.1007/s42235-024-00507-5

Role of Multi?scale Hierarchical Structures in Regulating Wetting State and Wetting Properties of Structured Surfaces

Yue Jiang1 · Xinyi Li2 · Zhichao Ma3 · Zhihui Zhang1  · Cuie Wen4 · Zhonghao Jiang5 · Nan Lin6 · Luquan Ren1

1 Key Laboratory of Bionic Engineering of Ministry of Education, College of Biological and Agricultural Engineering, Jilin University, Changchun 130022, China

2 Hubei Provincial Engineering Technology Research Center for Microgrid, College of Electrical Engineering and New Energy, China Three Gorges University, Yichang 443002, China

3 School of Mechanical and Aerospace Engineering, Jilin University, Changchun 130025, China

4 Centre for Additive Manufacturing, School of Engineering, RMIT University, Melbourne, Victoria 3001, Australia

5 Key Laboratory of Automobile Materials of Ministry of Education, College of Materials Science and Engineering, Jilin University, Changchun 130025, China

6 State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130012, China

Abstract

Amplifying the intrinsic wettability of substrate material by changing the solid/liquid contact area is considered to be the main mechanism for controlling the wettability of rough or structured surfaces. Through theoretical analysis and experimental exploration, we have found that in addition to this wettability structure amplifcation efect, the surface structure also simultaneously controls surface wettability by regulating the wetting state via changing the threshold Young angles of the Cassie–Baxter and Wenzel wetting regions. This wetting state regulation efect provides us with an alternative strategy to overcome the inherent limitation in surface chemistry by tailoring surface structure. The wetting state regulation efect created by multi-scale hierarchical structures is quite signifcant and plays is a crucial role in promoting the superhydrophobicity, superhydrophilicity and the transition between these two extreme wetting properties, as well as stabilizing the Cassie–Baxter superhydrophobic state on the fabricated lotus-like hierarchically structured Cu surface and the natural lotus leaf.

Keywords Hierarchical structure · Wetting state regulation · Wetting transition · Superhydrophobicity · Superhydrophilicity