Facile fabrication of a durable polydimethylsiloxane-silica-coated aluminum mesh with superhydrophobic behavior for efficient oil-water separation.

Abstract

Oil leakage is a major environmental concern, making the separation of oil-water mixtures increasingly crucial. A practical and cost-effective solution involves using a superhydrophobic metal mesh for efficient oil removal from oily wastewater. In this paper, we propose a method that employs a facile approach to fabricate silica/polydimethylsiloxane (SiO₂/PDMS)-coated aluminum meshes with superhydrophobic properties for oil-water separation. The fabrication process begins by coating an aluminum mesh with a PDMS layer through a dipping method. Next, hydrophobic fumed SiO₂ nanoparticles are applied to the coated mesh under low-vacuum condition, which effectively suppress crack formation during curing. After curing, this process forms thick hierarchical micro/nano structures on the mesh, yielding excellent superhydrophobicity, characterized by a contact angle greater than 150° and a sliding angle lower than 10°. We also investigated the durability and the oil-water separation capabilities of the superhydrophobic mesh. The fabricated mesh demonstrated strong superhydrophobicity, evidenced by water droplet contact angles exceeding 150° after 100 cycles of sandpaper abrasion as well as after 15 min of exposure to water flow impact owing to the thick hydrophobic silica/PDMS coating. Furthermore, it achieved oil-water separation efficiencies of over 91 % with three different oil-water mixtures. This easy and rapid fabrication method utilizes commercially available materials, making it ideal for mass production and industrial applications in large-scale oil removal.