The sol-gel process is very long known since the late 1800s. The versatility of the technique has been rediscovered in the early 1970s when glasses where produced without high temperature melting processes. This made possible the organic modification of silicon compounds (ORMOSIL), which cannot withstand high temperatures. As there is a huge field of possibilities for these organic modifications, the process can be used to introduce functionalities.

Concerning the coating of wood coloring, toughening and biocide treatment by means of a sol-gel technique have been suggested without realizing functionalized wood so far.The coating of thermally treated wood for indoor use is a completely new powerful approach of functionalizing in an easy, cheap, sustainable and flexible way. During the sol-gel process the functionalized monomers (= precursors) are partly hydrolyzed in a defined way. This leads to polymerization and cross-linking so that nanoparticles with a diameter of ca. 10 nm are formed.

These nanoparticle sols can be applied to the wooden surface by conventional coating techniques like dipping, spraying and brushing. After drying a functionalized layer of about 20 nm thickness is achieved. Functionalities to be incorporated are coloration, hydrophobic, hydrophilic (“easy-to-clean”), oleo phobic, biocide and anti-static (if necessary) properties but also fire retardant and non technical functionalities like anti-sliding and haptics – the surface feel (i.e. velvet or leather); these are the properties most desired by customers.

One special advantage of the proposed technique is the possibility of the formation of chemical bonds between the coating and the wood surface by means of the present functional alcoholic groups.

Therefore the durability of the coating will be high so that the functionality does not get lost by cleaning procedures (see Figure 1). Work to be done during the project comprises laboratory experiments, where the precursors are synthesized and the sols are prepared and subsequently applied to glass and thermal treated wood samples.

The target functions and the surface structure are analyzed and tested with the appropriate methods.

In the following the different sols containing the different functionalities will be combined by mixing in order to test the applicability of the modular system. This design allows quick and satisfying response to different and changing customer’s requirements and is the perfect instrument in days of rapid progress. In the next step, the production of the sols will be scaled up to technical scale.

The module parts will be scaled up, too and tested under real conditions during the prototyping procedures. After successful completion of all tests (incl. approval procedure), the coated thermally treated wood will be produced at industrial scale.

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