Wear resistance of nanoparticle coatings on paperboard

• LFS-deposited nanoparticles, TiO2 and SiO2, modify wettability of paperboard.
• Wear resistance of nanocoating is investigated through exposure to rotary abrasion.
• Abrasive damage of surface structure influences only slightly the wettability.
• The wear resistance depends on the nanoparticle material type used.
• SiO2 nanoparticle surface coatings are more wear resistive than TiO2 nanocoatings.

Paper can be coated with liquid flame spray (LFS) generated nanoparticles to control the wettability of its surface from hydrophilic to superhydrophobic. The adhesion of the nanoparticles on paper is of interest both for understanding the product durability during its lifetime and for product safety issues. Poor particle adhesion influences the desired functional properties and released nanoparticles cause health and environmental concerns. To investigate the wear resistance of LFS-TiO2 and -SiO2 coated papers, the nanoparticle surfaces were exposed to rotary abrasion tests. The changes in the samples were analyzed by contact angle measurements and high resolution field-emission scanning electron microscopy (FESEM). After abrasive action with another paperboard surface, only relatively small changes in wettability of superhydrophobic/hydrophilic coatings were found. A more severe abrasive action will remove some of the nanoparticle coating, but the hydrophobic/hydrophilic character of the surface is still maintained to large extent. The results indicate that the wear resistance of LFS nanocoated paper surfaces differs and depends on the nanoparticle material type used for the coating. This is clearly reflected as changes in surface structure shown by FE-SEM and wettability. The results can help understanding which paper-related application areas could be targeted with the LFS-nanoparticle coating process.