Plasma treatment of wood and wood-based materials to generate hydrophilic or hydrophobic surface characteristics

Plasma treatment at atmospheric pressure using a dielectric barrier discharge was carried out to increase the surface hydrophilicity of wood and wood-based materials. Surface energy determination by contact angle measurement revealed an increase in the polar component of surface energy and in total surface energy following plasma treatment. X-ray photoelectron spectroscopy revealed the generation of polar groups and consequently an increase in O/C ratio. The feasibility of plasma polymerization on wooden substrates at atmospheric pressure to create water-repellent characteristics was also investigated. An atmospheric-pressure plasma jet using hexamethyldisiloxane as precursor and air as process gas was used for thin-layer deposition. Treatment parameters for the layer deposition were investigated, as well as the layer topography and chemical composition. Atomic force microscopy revealed a closed surface layer consisting of silicon, oxygen, carbon and hydrogen that exhibited low water permeability.