Determination of the surface fractal dimension from sorption isotherms of five softwoods

This paper presents the determination of the surface fractal dimensions fro m water adsorption/desorption data of five softwood species by using three different methods. The Frenkel-Holsi-Hill model of polymolecular sorption o n a fractal surface by allowing capillary condensation is shown to be the b est method. Using this method, the fractal dimensions were found to be clos e to 2.5 and 2.4 from desorption and adsorption isotherms respectively. Mor eover, they were shown to slightly vary between species, and between sapwoo d and heartwood for the temperature range of 30 to 60 degrees C, but with n o clearly identifiable temperature effect.