Surface Wettability of Wood Species from Tropical and Temperate Zones by Polar and Dispersive Liquids

Wood species from Africa, South America and Europe, primarily used as a fl ooring and construction material, were acquired for the study. Wettability was determined using the measurement of the contact angle of wood with the reference liquids (water, diiodomethane) based on the sessile drop method. Surface free energy of wood on tangential sections within fi rst 60 s after applying a drop was determined. Among the species from the tropical zone, the greatest hydrophobicity, similar to oak wood, was characteristic for courbaril wood. After 60 s, the value of the surface free energy for the heartwood of the studied species was between 60 and 70 mJ·m-2, while for the sapwood of pine and birch, it was about 80 mJ·m-2. The biggest changes in the work of adhesion, within 60 s after the application of a drop of water on the surface of the wood, was stated for pine sapwood, and the smallest one for tauari and courbaril wood.