Cam yüzeyler i̇çi̇n fonksi̇yonel yüzey kaplama materyalleri̇ni̇n hazirlanmasi ve geli̇şti̇ri̇lmesi̇

Surface properties are important benchmarks which effect appearance and end of use of a matertial. Modification of the surface properties provides advantages in terms of application and appearance. In latest researches wettability of the surfaces has found to be an important property in this subject. Wettability of the surface has been associated with the hydrophobic property of the surface. Hydrophobicity in chemistry literature means water avoidance feature. This feature is seen on the nature of some plants and animals, for example lotus flower which has superhydrophobic leaves is always clean although it is living in swamps. Hydrophobic surface is non-polar. Therefore, when water drops on a surface, water molecules do not bond to hydrogen molecules, they bond to each other. When the water drop slides from the surface it drags impurities on the surface. This provides a self-cleaning feature. Thanks to this feature Lotus flower utilizes sun rays at a maximum level for the photosynthesis by keeping its leaves clean. This situation called "Lotus Effect". Feature of lotus leaf has led to emergence of new ideas and started biomimetic studies. In this study the hydrophobic charechteristic is imparted to the Al and glass surfaces by using sol-gel and PDMS-Silica method for the preparation of the coating material. To enhance roughness of the surface, chemical etching method has been applied to the aluminum substrates before coating. Chemical etching has been done by an acidic solution. Coating solutions were prepared with fluoroalkylsilane and alkoksysilane based materials by using sol-gel method. To obtain a durable and roughness enhanced surface morphology like Lotus flower's surface, different alkoxysilanes are used. The coating materials which are prepared by sol-gel method are applied to Al surfaces by spin coating methods. The hydrophobic properties of the Al and glass surfaces are investigated by changing chemical composition of the coating solutions. Coated Al and glass substrates are evaluated by water contact angle measurements. Furthermore, the relationship between coating material composition and process parameters are investigated. In order to obtain anti-icing surfaces, superhydrophobic property is imparted to aluminium surfaces. To this end fluoroalkysilane (FAS) topcoated polydimethylsiloxane (PDMS) silica nanocomposite coatings have been generated. Coatings were coated on the aluminium plates with spin and sprey coating method. Coated surfaces has been cured to enhance durability and efficiency of the coatings. The improved hydrophobicity was attributed to the combined effect of low surface energy of FAS and roughness created by the random distribution of silica nanoparticles. By changing the silica type, FAS type and curing conditions the effect of these parameters have been investigated. Chemical composition of the coatings were investigated by FTIR and SEM and AFM was used to define surface morphology. Hydrophobic property of coated Al and glass substrates are evaluated by water contact angle measurements. Anti-icing property imparted to the aluminium surface was observed by icing test on a coated and uncoated refrigerator evaporator in the controlled media simulatiıng refrigerator working conditions. Test results showed that by coating the evaporator with PDMS-Silica+FAS coating the icing was decreased and delayed. Keywords: Hydrophobic coatings, superhydrophobic surface, lotus effect, sol-gel method, nano-composite coating, polydimethylsiloxane