Volume 20 (12/2008)
No chance for wetness! Surface science for optimal wood protection
About 80 years ago Dr. Karl Wolman developed the pressure impregnation method for preserving wood. Thanks to this technique the active agents penetrate the wood deeply and uniformly, which gives it long-term protection against wood pests and fungal infection and makes it fit for outdoor use. Pressure-treated wood is on the market in different classes based on the amount of active agent absorbed per cubic meter; this determines the field of use for the wood depending on ambient conditions such as soil contact or wetness.
In order to protect the wood surface against weathering the pressure-treated wood is frequently additionally coated – hundreds of products for final treatment are currently on the market. Our Application Department cooperates with various manufacturers to investigate the influence of the pressure-impregnation and active agent content on the long-term stability of such a coating. The determination of the interfacial tensions in the coating, water and wood triangle provides useful information.
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Practical contact angle measurement (5): Custom-made models - from contact angle to surface free energy
The determination of the surface free energy (SFE) of a solid is the ultimate in contact angle measuring techniques. The method provides the user with important information about the material surface, such as its wettability and adhesiveness. In order to plan a measurement and draw the correct conclusions from the results a good knowledge of the scientific models upon which these are based is useful.