Wetting of wood

Summary Thermodynamic work of adhesion, contact angle, wettability and acid-base contributions of the wetting of four North American wood species were determined using the Wilhelmy technique. The wetting angles with water varied from 60° for Sitka spruce to 74° for Douglas-fir. The wood surfaces had a strong acidic character since the greatest interactions for all the wood species occurred with formamide (basic probe) while lesser interactions were obtained with ethylene glycol (acidic probe). In addition, dispersive and polar surface free energies of wood, _d ^s and _p ^s respectively, were determined using Wu's simultaneous equations. In general, 75 to 80% of the total surface free energy of wood was due to dispersion forces. Specific wettabilities of wood and advancing contact angles in thirty various organic liquids were also evaluated.