THEORY AND PRACTICE OF THIN-LAYER WICKING

Theoretical considerations and experimental results are presented for the wicking process of a solid thin porous layer. This method was used for the solid surface free energy determinations. The commercial silica covered glass plates (Merck), used in thin-layer chromatography, were applied as a model material to check the derived equations as well as the experimental procedure. It is shown that the theoretical derivations, originating from Washburn's equation, and the obtained experimental results are consistent. The method should be especially useful for the solids of which a flat plate, suitable for contact angle measurements, cannot be obtained.