Wood surface energy and time dependence of wettability: A comparison of different wood surfaces using an acid-base approach

Using four different wood species, the wetting behaviour of sanded wood surfaces was compared with that of microtomed surfaces. Sanding caused lower contact angles and lower total surface free energies. Electron donor components were considered to be responsible for the observed changes according to the applied acid-base approach. The time behaviour of sanded surfaces differed from the microtomed reference, insofar as the volume of a deposited drop of water decreased very rapidly as soon as it was applied, indicating fast penetration into the wood. A qualitative, analysis by SEM revealed a heavily torn uppermost cell layer on sanded surfaces, which was assumed to be responsible for the increased surface free energy and enhanced penetration.