Preparation of Fluorine- and Nanoparticle-Free Superwetting Cellulose Composites Via Modifying with Main-Chain-Type Furan-Based Polybenzoxazines for Efficient Oil/Water Separations

Considering the dangers of spilled oil, it is important to develop economical materials for the rapid removal of oil contaminants. Herein, we report the successful synthesis of a furan-based polybenzoxazine (Fu-PBZ) and present an easy method for preparing robust superhydrophobic surfaces on a cotton fabric and filter paper, using a non-solvent-induced phase inversion method. The cured Fu-PBZ possessed unusual flexibility, low surface free energy (as low as 13.5 mJ m-2), and an extremely high glass transition temperature. The Fu-PBZ-modified cotton fabric (Fu-PBZ@CF) and Fu-PBZ-modified filter paper (Fu-PBZ@FP) both possessed superhydrophobicity and superoleophilicity. Fu-PBZ@CF exhibited excellent separation performance for versatile oil/water mixtures with permeation fluxes of up to 116,000 L m-2h-1 and efficiency greater than 98%. Fu-PBZ@FP exhibited a permeation flux of up to 5010 L m-2h-1 and oil purity greater than 99.96% in separating the surfactant-stabilized water-in-oil emulsions. The low surface free energy and hydrophobicity of the binder polymer provided by the self-roughness of the Fu-PBZ coating assisted the substrates in recovering their superhydrophobic property even after repeated applications, rendering our modified materials a viable candidate for practical applications.