Easy-to-clean coatings on glass and glazed surfaces

摘要

Glass and glazes are easy-to-clean surfaces often used in everyday environments where the surface needs to repel soils and deposits. In general, these surfaces have good chemical durability in everyday environments. However, the durability is rapidly degraded in solutions of high or low pH. This kind of surface corrosion has been found to diminish the cleanability. Surface topography has also a certain influence on the soil attachment and cleanability. Self-cleaning and easy-to-clean coatings have been employed to enhance the cleanability of surfaces. In this report surface properties of three coatings reported to enhance the cleanability of glass and glazed surfaces are summarized. The properties discussed are the surface appearance, roughness, wettability, soil attachment and soil removal. Also the chemical and mechanical durability of the coatings are discussed. The coatings studied were a commercial fluoropolymer film applied at room temperature, an experimental sol-gel derived TiO_2 coating calcined at 500°C, and an experimental liquid flame sprayed TiO_2-Ag coating applied on the substrates at 500-800°C. The advantages of the fluoropolymer coating are easy application and soil good soil repellence, but the coating has limited chemical and mechanical durability. The manufacture of the sol-gel TiO_2 coating requires several processing steps. The coated surface showed excellent cleanability, and good chemical and mechanical durability. The liquid flame sprayed coating has potential to be applied online in the material manufacture. However, the processing parameters should be optimized in order to achieve desired improvements in the cleanability.