Work

Fabrication of bioinspired dual-scale needle-like micro/nanostructures for efficient oil–water separation

Year: 2025

Type: article

Abstract: Inspired by the morphology of cactus spines and their water collection ability, this study presents dual-scale needle-like micro/nanostructures (DNMNs) for efficient oil–water separation. The DNMNs are fabricated via a two-step process comprising laser etching followed by high-temperature oxidation. The effects of laser etching and oxidation parameters on the DNMN morphology are systematically investigated. The results show that the laser power controls the geometric dimensions of the microneedle arrays by adjusting the energy distribution. Optimized oxidation conditions (500°C, 2 hours) promote the formation of uniform and high-density nanoneedles. The obtained DNMNs exhibit outstanding superhydrophobicity and superoleophilicity after fluorination modification, with a water contact angle of 158.4° and an oil contact angle of approximately 0°. Theoretical analysis indicates that the synergistic effect between surface wettability gradients and structure curvature pressure drives the directional transport of oil droplets. Oil–water separation experiments confirm that the DNMNs can rapidly adsorb both light and heavy oil droplets, achieving efficient and complete adsorption of both floating and submerged oil droplets on the water surface. This study provides a new strategy for micro/nanostructured functional surfaces in oil–water separation applications and lays a crucial theoretical and experimental foundation for the design of micro/nanostructures.

Source: Colloids and Surfaces A Physicochemical and Engineering Aspects

DOI: 10.1016/j.colsurfa.2025.138984