One-Step Process for the Fabrication of Hydrophobic and Dimensional Stable Wood Using Functionalized Silica Nanoparticles

The aim of this research was to improve the dimensional stability of wood through bulk hydrophobization, as a result of impregnation with fluorinated silica nanoparticles. The wood species European beech (Fagus sylvatica L.) and Scots pine (Pinus sylvestris L.) were used. The characterization of the modified wood was performed using analytical methods, including scanning electron microscopy, energy dispersive X-ray spectroscopy, and Fourier-transform infrared spectroscopy. The effect of fluorinated silica nanoparticles on the anti-swelling efficiency, water uptake, equilibrium moisture content, and water contact angle were investigated. The surface of the cell walls was discontinuously covered with fluorinated silica nanoparticles forming a rough surface coating. The presence of the hydrophobic silica nanoparticles improved the dimensional stability by permanently increasing the hydrophobicity of wood, besides a low weight percent gain. Furthermore, the treatment significantly decreased the equilibrium moisture content and water uptake. The modified wood surfaces showed significantly higher water contact angles, which was the main reason of the improved dimensional stability.