Investigation of beech wood modified by radio-frequency discharge plasma

• Beech wood was treated by eco-friendly discharge plasma to improve adhesion.
• The surface free energy of beech wood increased significantly due to plasma effect.
• The hydrophobic recovery during aging was not leading to the initial state.
• The enhancement of the wettability of beech wood led to the adhesion improvement.

Low-temperature plasma was used to improve the surface and adhesive properties of wood. The pre-treatment of wood surfaces using radio-frequency (RF) discharge plasma is attractive for various wood applications, mainly because of the high efficiency and low production cost of the process. In addition, a significant increase in the polar component of the wood surface energy, which is associated with the presence of acid–base interactions (electron donor–acceptor bonds), after modification by RF discharge plasma was identified. The treatment of wood by RF plasma exhibited an aging effect, with the modified surface never recovering its initial hydrophobic state. Indeed, the enhancement of the wettability of wood is necessary for promoting better adhesion with water-based adhesives and coatings, which is currently the subject of ongoing study.