By Microporous Oxides Science & Technology, LLC
These images illustrate thin-film coatings when applied to surfaces. The thicknesses of these coatings are on the order of one micron. Coating thickness depends on several factors that can be controlled during the coating process, although these factors also depend on whether the substrate is dip coated or spray coated. MOST is capable of applying these coatings to hydrophilic and some hydrophobic surfaces (or supports). Coatings can be applied to substrates with rough surfaces but are likely to produce a non-uniform thickness. However, as long as the substrate wets well, all parts of a substrate with a rough surface are likely to be coated to some extent. The properties of the thin-film coatings that can be produced using MOST’s nanoparticle sols depend on the temperature used to heat the coating. This image shows a ceramic wall tile that has been coated with MOST’s titania sol up to the hole in the corner of the tile and then heated to 700 C to produce a non-porous coating. The hardness of this coating has not been completely determined but is greater than 5 on the Mohs Hardness Scale. The accompanying figure shows three paper sheets printed with visible light spectra that have been exposed to a UV light source for the same length of time (click to zoom). Sheet A (far left two columns) is a control that has not been coated. The colors have clearly faded considerably when compared to the other two coated sheets. A silica coating was applied to Sheet C (far right two columns), which faded much less than the uncoated control. A silica undercoat was applied to Sheet B (middle two columns) followed by a titania overcoat, and you see the least amount of fading, retaining the most pure color.
