Application and characterization of a novel PVDF-HFP/PVP polymer composite with MoO3 nanowires as a protective coating for wood

The coatings on wood must sometimes give aesthetic and basic protection to wooden elements and prevent the development and transmission of microorganisms. Several polymers containing different nanoparticles have already been offered to day for this purpose. A present research presents a novel poly(vinylidene fluoride-co-hexafluoropropylene (PVDF-HFP)/polyvinylpyrrolidone (PVP) polymer composite with MoO 3 nanowires with the ability to form coating films on wood. The films of the developed coating exhibit elastic behaviour, which depends on the coating film thickness (tested wet film thicknesses 90 µm, 180 µm and 360 µm). The developed coating showed the ability to interact well with the surface of common beech (Fagus sylvatica L.), in terms of wetting (contact angles of 15.6°), fast spilling on the surface, good penetration of the coating in wood structure, formation of up to 40 µm-thick films with excellent pull-off adhesion strength (6 MPa). An increased roughness of wood coated with C + MoO 3 was a consequence of wood etching by the dimethylformamide solvent present in the coating. Moreover, the presence of C + MoO 3 on wood made it considerably more hydrophobic, with contact angle of water droplets raising to 123° from initially 46° measured on uncoated wood. The irradiation of wood surfaces with ultra-violet light resulted in colour changes on both uncoated and coated wood, visible to the naked eye. The wood samples coated with C + MoO 3 has a good resistance to water, alcohol and dry heat (grade 3 to 4). The antimicrobial testing showed that the presence of MoO 3 in the developed coating plays an important role in the resistance of the coated wood blue-stain fungi and mould development. The developed PVDF-HFP/PVP/MoO 3 coating has an excellent ability to interact with the wood surface and has the potential to be used as a protective coating for wood in sensitive environments.