(458a) Liquid Flame Spray Deposited Nanocoatings On Painted Metal

Objects often have some surface finishing, e.g. paint or lacquer. There is a need to alter the surface properties of these kinds of surfaces as well. Here, we introduce the Liquid Flame Spray (LFS) method to alter the contact angle of surface treated metal. There will be great additional value for painted surfaces, as well. For example roof tops and cars need not to be cleaned that often if there is a hydrophobic coating on top for the running water will clean the surface. Previously, we have applied TiO₂ coatings on metal and glass in order to have photocatalytic surfaces [e.g. Keskinen et al. 2006]. Now, we painted metal sheets using ordinary paint and lacquered some of those as well. TiO₂ coating is deposited on the surface straight from the LFS. The painted surface is quite porous, which increases the yield. However, painted surfaces cannot take up as much heat as clean metal surfaces. Therefore, the processing temperature needs to be controlled more carefully. TiO₂ particles are produced from Titanium(IV) isopropoxide dissolved in isopropanol. The solution is sprayed into a hydrogen-oxygen flame and the particles form via a gas phase synthesis inside the flame. The particles are then deposited on the substrate to form a coating by sweeping the surface through the flame. First tests show an improvement in contact angle from a reference of 110° to 150°.

Keskinen H., Mäkelä J. M., Aromaa M., Keskinen J., Areva S., Cilâine V. T., Rosenholm J.B., Pore V., Ritala M., Leskelä M., Raulio M.,Salkinoja-Salonen M. S., Levänen E. and Mäntylä T. (2006) Deposition of Titania and Titania-Silver Nanoparticles by Liquid Flame Spray and Their Application as a Photocatalyst, Catalysis Letters, vol. 111, pp.127-132