High-strength and super-hydrophobic multilayered paper based on nano-silica coating and micro-fibrillated cellulose

Herein, a facile strategy was proposed for preparing a high-strength and super-hydrophobic packaging paper with improved moisture and air barrier properties, which was derived from cellulosic pulps, micro-fibrillated cellulose (MFC), and nano-silica (n-SiO₂). Owning to the laminated process followed by spraying approach, MFC and n-SiO₂ were assembled onto two surfaces of the cellulose paper base, respectively, endowing the mechanical behaviors and superhydrophobic performance of this biodegradable composite papers as packaging material. The as-obtained multilayered papers demonstrated impressive dry tensile strength and remarkable wet tensile strength of 6542.5 N/m and 5875 N/m, which were increased by 56% and 2277%, respectively. In addition, the multilayered paper with rational mechanical properties possessed low permeabilities of air (3.17 × 10^-3 μm·Pa^-1·s^-1), oxygen (9.687 cm³·m^-2·day^-1·atm), and water vapor (378.24 g·m^-2·day^-1), respectively, as well as a superhydrophobic performance with the contact angle of ~151.2°. Overall, the feasibility of large-scale production of biodegradable packaging materials in the paper-making industry is demonstrated by the fact that the micro/nanostructures and hydrophobic surfaces could be directly constructed on cellulosic paperboard.