Multi-functional nano-materials for timber in construction

The role of nano-materials in extending the life and maintaining the appearance of timber in construction is reviewed. Nano-materials in timber coatings may be biocidal, ultraviolet-resistant, self-cleaning, anti-wetting, fire-resistant, scratch-proof and deacidifying. There is also scope for impregnating timber with nano-materials to increase thermal conductivity and hardness. The recent literature on nano-materials for timber is reviewed including nano-silver (biocide), nano-titania (photocatalytic, self-cleaning), nano-metal oxides, for example silica (SiO2), zinc oxide (ZnO), alumina (Al2O3) (ultraviolet stability, gloss retention, durability), clays (mechanical properties, hardness) and nano-limes (deacidification and hardness). There is a wide choice of nano-materials for timber and their high surface area to mass ratio ensures that a loading of only a few percent by weight in coatings is able to significantly enhance chemical, thermal and physical properties. Although there are already commercial timber coatings that contain nano-materials, there is considerable scope for improving their performance and chemically binding nano-materials directly to the wood cell wall.