Surface properties of sol-gel treated thermally modified wood

The application of inorganic sol coating agents is a versatile method for wood surface functionalisation. However, the use of sols for the surface finishing of thermally modified wood (TMT) so far has not been investigated thoroughly. This paper reports on the surface properties of TMT treated with modified silica sols. The silica sols are modified with the inorganic colour pigment iron oxide red. Pigment distribution and height profiles of sol treated TMT are characterised by optical microscopy in 3D mode and by scanning electron microscopy. Selected evaluations are also repeated after artificial weathering of the coated wood specimens. Hydrophobic surface properties are determined using contact angle measurements. The coloration can be adjusted by the degree of pigmentation of the applied nanosol. Moreover, the water repellency of TMT is significantly enhanced by the sol treatment. Therefore, the application of pigment modified nanosols could lead to TMT with improved weathering stability and a wider coloration spectrum.