The fluorine-free coating has excellent hydrophobic and oleophobic properties for porous cellulose-based materials

Nanofibrillated cellulose is obtained from cellulose resources (e.g., Natural cellulose, bacterial cellulose) and is deemed to be environmentally friendly, green, and inexhaustible. Accordingly, we reported an innovative method for fluorine-free water-and oil/grease-repellent surface based on porous cellulose-based materials. In order to improve oil/grease resistance, sulfonated nanofibrillated cellulose (SNFC) was coated on the surface to fill the porous, the obtained paper was soaked in chitosan aqueous solution as the second layer. The-SNFC-chitosancoated paper was applied with modified polyvinyl alcohol (MPVA) as the third layer to increase water resistance and water vapour transmittance. The experimental results showed 5.2 g/m(2) SNFC, 2.5 g/m(2) chitosan and 7% MPVA demonstrated excellent kit rating value of 12/12 (maximum grease resistance) (oil resistance contact angle is 103.93 degrees), good water resistance (water contact angle is 108.6 degrees) and high water vapour transmission rate (4.8 x 10(-14) g cm/cm(2) s Pa) under the condition of 90% relative humidity. This non-fluorinated and practical method is an excellent alternative to existing fluorinated materials, which will further promote the development of cellulose-based packaging. [GRAPHICS] .

Automated summary

The study presents an innovative surface coating method based on nanofibrillated cellulose, demonstrating excellent oil/grease resistance and water vapor transmittance without the use of fluorine. By combining sulfonated nanofibrillated cellulose, chitosan, and modified polyvinyl alcohol in multiple layers, the coated paper shows a high kit rating value for grease resistance, good water resistance, and high water vapor transmission rates under specific conditions.