Peristome-Mimetic Surfaces Fabricated by Nanosecond Laser for Unidirectional Liquid Spreading

Unidirectional liquid transport, which operates without external energy input, has garnered remarkable interest in the global energy sector. A crucial breakthrough in this field involves understanding how liquids spread on the peristome surface of Nepenthes alata. This study, inspired by the microstructural traits of the Nepenthes peristome, has brought about the development of a biomimetic surface on metal substrates using nanosecond laser processing on inclined bases. This process replicates the natural peristome's microstructure, which allows for controlled liquid spread on the surface. The research also examines how wettability influences unidirectional liquid spread. Additionally, it involves adjusting the microstructure parameters on the biomimetic surface, which leads to variations in edge curvature and microcavity wedge angles. More importantly, this study comprehensively investigates the relationship between these structural changes and the phenomenon of unidirectional liquid transport. The findings suggest that altering edge curvature and microcavity wedge angles can manage the directional spread of liquids. The optimized surface, with ideal curvature and wedge angles, achieves liquid movement speed up to 12.03 mm s(-1). This represents a notable improvement, 2.2 and 2.7 times faster than the original structure, respectively. These findings provide valuable insight into the design of energy-independent unidirectional liquid spreading surfaces on metal substrates.