Mikko Aromaa1, Jyrki M. Mäkelä1, Helmi Keskinen1, Minna Piispanen2, Leena Hupa2, Knut Deppert3, Jakob B. Wagner4, L. Reine Wallenberg4, Joe Pimenoff5, Maria Lang6, Peter Sundberg6, Stellan Persson6, Thomas Kronberg7, Viljami Pore8, Mikko Heikkilä8, Mikko Ritala8, Markku Leskelä8, Mari Raulio9, Mirja S. Salkinoja-Salonen9, and Veli-Matti Airaksinen10. (1) Aerosol Physics Laboratory, Tampere University of Technology, PO Box 692, FIN-33101, Tampere, Finland, (2) Process Chemistry Centre, Åbo Akademi University, Biskobsgatan 8, FIN-20500, Turku, Finland, (3) Solid State Physics, Lund University, Box 118, S-221 00, Lund, Sweden, (4) Polymer and Materials Chemistry, Lund University, Box 118, S-221 00, Lund, Sweden, (5) Beneq Oy, Ensimmäinen Savu, FI-01510, Vantaa, Finland, (6) Glafo, Glass research institute, Box 5157, SE-350 05, Växjö, Sweden, (7) IDO Bathroom Ltd, FI-10600, Ekenäs, Finland, (8) Laboratory of Inorganic Chemistry, University of Helsinki, PO Box 55, Helsinki, Finland, (9) Applied Chemistry and Microbiology, University of Helsinki, PO Box 55, Helsinki, Finland, (10) Microelectronics centre, Helsinki University of Technology, PO BOX 3500, FI-02015 TKK, Espoo, Finland
Flame methods are a promising way to manufacture nanoparticles in commercial scale. They are widely utilized already. In this study, a process called Liquid Flame Spray, LFS, is used. It is commercially known as nHALO (Hot Aerosol Layering Operation, Beneq Oy). In LFS, liquid precursor is fed into a turbulent hydrogen-oxygen flame. LFS can be used in production of nanoparticles which are deposited on a substrate. Even multicomponent nanoparticles can be manufactured using LFS process.
LFS is a versatile method for nanoparticle generation. In this study, we use LFS to produce an anti-microbial titania-silver nanoparticle coating on ceramic tiles and float glass [Keskinen et al. 2006]. The coating is produced by collecting TiO2-Ag nanoparticles directly from the flame. The particles are deposited on the surface. Some of the excess particles are not properly attached. The coating is then characterized using electron microscopy, contact angle measurements, organic and biofilm removal tests and bacterial tests. Scanning Electron Microscopy (SEM) images indicate that the titania-silver coating covers the tiles even after scrubbing away the loosely adhered particles. Tunnelling Electron Microscopy can be used to obtain information about the particle morphology. TEM micrographs suggest that the coating is formed of 10 to 20 nm TiO2 particles and small Ag nanoparticles on the surface of TiO2. The size of the Ag particles is few nanometres.
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