Sprayable, durable, and superhydrophobic coating of silica particle brushes based on octadecyl bonding and polymer grafting via surface-initiated ATRP for efficient oil/water separation

Abstract

Abstract A facile approach to prepare sprayable, durable, and superhydrophobic coating was designed for highly efficient oil/water separation and oil absorption based on silica particle brushes via surface-initiated (SI-ATRP). Octadecyl group bonded and poly(styrene-co-acrylonitrile) (PSAN) grafted silica nanoparticles (NPs) (C18-SiO2-g-PSAN) were prepared by sequential initiator tethering and SI-ATRP processes, which were directly applied as surface superhydrophobic coating for various porous substrates. The results confirmed that octadecyl group and PSAN were successfully bonded on silica NPs. After facile spraying of C18-SiO2-g-PSAN, the coated porous substrates displayed superhydrophobicity with an advancing water contact angle (WCA) exceeding 150° due to the synergistic effects of low surface energy compositions contributed by the tethered octadecyl group and the rough structure induced by silica NPs and porous substrates. Superhydrophobic porous substrates exhibited high oil/water separation efficiency achieving 98.8% by using cotton fabric as substrate and remarkable oil absorption capacity of 39.2 g/g for isooctane using polyurethane sponge as substrate. The recyclability and strong durability against mechanical abrasion enable them to be promising candidates for industrial oil-contaminated water treatments and marine spilt oil cleanup in harsh environments.