Estimating the wettability of wood by the axisymmetric Drop Shape Analysis-contact diameter method

Summary The wettability of four wood species was determined by the Axisymmetric Drop Shape Analysis-contact diameter (ADSA-CD) technique. The ADSACD technique calculates the contact angle by solving the Laplace equation of capillary given the following variables: contact diameter, volume of the liquid drop, liquid surface tension, density difference between the two fluid phases and the gravity constant. The liquid surface tension, density, and gravity are known. The volume of the liquid sessile drop is obtained by means of a micrometer screw syringe. The contact diameter, the only main experimentally determinable variable is obtained by manually selecting an arbitrary set of coordinates characterizing 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 angles on wood surfaces.The authors wish to acknowledge the financial support of the Ontario Centre for Materials Research, The University of Toronto, and the Natural Sciences and Engineering Research Council of Canada, grant Nr. A8278. Ms. Z. Policova is acknowledge for technical assistance