Mussel Adhesive-Inspired Design of Superhydrophobic Nanofibrillated Cellulose Aerogels for Oil/Water Separation

Abstract

Inspiration from biomimetics—the chemistry of mussel adhesives—was taken for imparting superhydrophobic properties to nanofibrillated cellulose (NFC) matrices. A polydopamine (PDA) surface coating was introduced, acting as an anchor between the NFC scaffold and octadecylamine (ODA): PDA is coated onto the NFC scaffolds by its adhesive properties and the ODA is successfully attached to the PDA by a Schiff base reaction. The ultralow density of 6.04 mg/cm3 combined with the high contact angle of 152.5° endows the composite aerogel with superb buoyancy and excellent oil/water separation selectivity. Oil can be rapidly absorbed from a mixture of oil and water. In addition, the modified aerogel can take up a wide range of organic solvents, with the maximum absorption capacity reaching up to 176 g/g, depending on the density of the liquids. The novel superhydrophobic aerogel shows great potential as an adsorber for oil and solvent spills and as an oil–water separator.