Green preparation of a cellulose nanocrystals/polyvinyl alcohol composite superhydrophobic coating

Abstract

Organic solvents, which are often used in the preparation process of superhydrophobic coatings, are volatile and toxic. The inorganic particles also widely used in their preparation are difficult to degrade, which may result in environmental contamination. In this study, commercial lignin-coated cellulose nanocrystal (L-CNC) particles, which are environmentally friendly and biodegradable and formed by CNC solution containing a small amount of lignin in a spray-drying process, uniting strength with a rough surface, were used to provide a good foundation for a superhydrophobic coating due to the different size and irregular surfaces of the particles. A superhydrophobic coating is successfully prepared by spraying a L-CNC/polyvinyl alcohol (PVA) composite paint and then modifying it via chemical vapor deposition (CVD). The resulting coating has not only good superhydrophobicity and self-cleaning properties, but also excellent abrasion resistance. In addition, no organic solvents or inorganic particles were used in the preparation process. Thus, this coating could potentially be used in some applications that require nontoxicity or environmental safety such as food packaging.