Fast net-forming of biomimetic hierarchical structures with robust oil/water separation performance.

Abstract

Biomimetic hierarchical structures (BHS) are a powerful strategy for engineering functional surfaces with exceptional properties. However, their practical application is limited by inefficient, costly and complex fabrication methods. This study presents a novel net-forming approach for the efficient, scalable fabrication of BHS inspired by the microstructure of rice leaves. By optimizing the tool surface design, the process achieves an ultra-low material loss of just 0.008‰ and a high processing efficiency of 18 mm²/s. The resulting BHS replicate the superhydrophobicity and anisotropic sliding behavior of rice leaves, while maintaining durable water repellency after more than 5000 hours of natural exposure and under severe abrasion. The method further offers substantial design flexibility, allowing the reconfiguration of BHS to accommodate diverse functions. This versatility is demonstrated by the fabrication of a mesh with BHS that exhibits efficient oil/water separation, achieving a separation efficiency of 99.07%, a flux of 2630 L·m^-2·h^-1 and notable self-cleaning ability. This work introduces a creative and scalable pathway for multifunctional BHS fabrication, significantly expanding their potential for real-world applications.