Nanostructured Copper Oxide-Based Interfaces for Liquid/Liquid and Liquid/Gas Separations

Development of an under-liquid super-repellent (ULSR) surface that can be used for separating both liquid/liquid and liquid/gas mixtures is strongly desirable, yet still hard to realize. Herein, to address this challenge, a Cu(OH) 2 nanowire textured surface on copper mesh was developed through a simple immersion process. The resulting Cu(OH) 2 nanowire surface displayed underwater superoleophobicity, underoil superhydrophobicity, and unusual dual superoleophobicity under immiscible oil-oil system. Exploiting its superlyophobic ity under-liquid, the Cu(OH) 2 nanowire covered copper mesh was applied to separate oil/water mixtures, emulsions, and oil/oil mixtures effectively, even though the surface tension difference between two liquids was just 2.4 mN/m. Owing to its superaerophobicity underwater and underoil, the obtained copper mesh was also able to separate gas from bulk water and oil efficiently. This work is hoped to provide a key addition to the fields of ULSR surfaces as well as membrane-based separation techniques