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Radial cuts of Pedunculate oak (Quercus robur L.) heartwood was activated by Diffuse Coplanar Surface Barrier Discharge (DCSBD) plasma. The plasma treatment resulted in a considerable increase of free surface energy and in the substantial reduction of 50 ll water droplet uptake time. FTIR analysis confirmed the formation of additional polar functional groups on the wood surface due to the plasma treatment. This is consistent with the shift of wood surface pH level towards more acidic values. The energy efficiency of the DCSBD plasma treatment is better comparing to the known volume dielectric barrier discharge treatment method.

The adhesion strength between the transparent acrylic or alkyd coatings and the Norway spruce (Picea abies Karst L.) wood was determined by EN ISO 4624 and analyzed concerning four variables: (a) fungicidal pre-treatment of wood with boric acid or benzalkonium chloride, (b) cold plasma modification of wood surfaces, (c) presence of hindered amine light stabilizer (HALS) or hydroxyphenyl-benzotriazoles (BTZ) in the role of UV-additives in coatings, and (d) weathering of coated wood—lasting 1 week in Xenotest by a modified EN 927-6, or 14, 28 and 42 weeks outdoors at 45° by EN 927-3. In the un-weathered state, the adhesion strength was positively affected by the initial plasma modification of wood surfaces, more evident with the application of acrylic water-borne coatings. On the contrary, the adhesion strength was not influenced by the fungicidal pre-treatment of wood and by the UV-additive’s presence in coatings. The adhesion was negatively affected by weathering—exponentially outdoor—irrespective of the fungicidal pre-treatment of wood, the plasma modification of wood surfaces, the coating type, and the presence of UV-additive in coatings.

Plant surfaces provide an unlimited source of systems for the protection of their surface against the outer environment. These systems have continuously improved over the last 400 million years of evolution. Two of the most fascinating properties of these systems are superhydrophobicity and the self-cleaning ability of several plant species. These properties are most often achieved due to the hierarchical structure of the surface in combination with a deposited blend of epicuticular waxes. In this study, a layer of n-hexatriacontane was deposited on wood surfaces via thermal evaporation, and the self-assembly ability was investigated for various wood species with differently machined surfaces. The behavior of wax crystals was observed using scanning electron microscopy (SEM) and confocal microscopy. The impact on wettability was investigated by measuring contact angles and tilt angles. With wax deposition, a significant change of wettability was achieved, which was represented by the transition from hydrophilic to superhydrophobic surface behavior. The self-assembly ability of n-hexatriacontane resulted in an increased contact angle in all observed samples.

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