ESTIMATING THE WETTABILITY OF WOOD BY THE AXISYMMETRICAL DROP SHAPE-ANALYSIS CONTACT DIAMETER METHOD

The wettability of four wood species was determined by the Axisymmetri c Drop Shape Analysis-contact diameter (ADSA-CD) technique. The ADSA-C D technique calculates the contact angle by solving the Laplace equati on of capillary given the following variables: contact diameter, volum e of the liquid drop, liquid surface tension, density difference betwe en the two fluid phases and the gravity constant. The liquid surface t ension, density, and gravity are known. The volume of the liquid sessi le drop is obtained by means of a micrometer screw syringe. The contac t diameter, the only main experimentally determinable variable is obta ined by manually selecting an arbitrary set of coordinates characteriz ing the perimeter of the sessile drop. The ADSA-CD technique was used on four wood species (pine, cedar, ash and elm) and it was found to be a simple, adaptable, and excellent tool for measuring the contact ang les on wood surfaces.