Hierarchical superhydrophobic surfaces for oil-water separation via a gradient of ammonia content controlling of dopamine oxidative self-polymerization

Superhydrophobic three-dimensional porous materials have been considering as one of the most promising candidate absorbents for removal and collection of oil spills or organic contaminants from water. In this work, we report a novel and straightforward method for construction of hierarchical superhydrophobic surfaces on the commercial melamine sponge by controlling of the dopamine oxidative selfpolymerization via a gradient of ammonia content. The surface roughness of the sponge was enhanced by the deposited polydopamine coatings whose surfaces exhibited different morphologies at solutions of varied ethanol-ammonia ratios. Thereafter the low-surface free energy moieties were decorated on the surfaces by utilizing a secondary modification platform of polydopamine. Correspondingly, the obtained superhydrophobic melamine sponge achieved a water contact angle of 162.6 degrees +/- 1. Furthermore, the superhydrophobic sponge exhibited excellent absorption performances and extraordinary recyclabilities toward a variety of oils and organic solvents. These findings presented in this study offer an effective and versatile approach for oil spills and organic solvents containment removal and environmental remediation in more fundamental and practical fields. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48044.