Nanoparticle surface coating

The wettability of solid surfaces is an important topic in material science and fundamental research. Because of their numerous potential applications, intensive researches have been done in recent years.Wetting of solid surfaces is characterized by the contact angle (CA). If the value of the water contact angle is greater than 90° and smaller than 150°, the surface is hydrophobic. Surfaces with the water contact angle between 150° and 180° are called superhydrophobic. For the preparation of superhydrophobic surfaces, should have both increasing surface roughness and decreasing surface energy. Generally, without roughness the maximum contact angle can not be increased more than 120°. Thus, for superhydrophobicity a great surface roughness is required. The high surface roughness achieved by nano-sized particles.In this study, nanocomposite surface was prepared by using nano-sized silisium dioxide (SiO2) and polystyrene (PS). For dissolving PS, which has been widely used preparing superhydrophobic surface, tetrahydrofuran (THF) and N,N dimethylformamide (DMF) were used. For investigating the effect of roughness on the wettability of surfaces, various mass percentage of SiO2 was used in coating which was prepared on glass and cupper surfaces. In addition, effects of various drying temperature on coatings were investigated.Scanning electron microscope (SEM) was used for investigating microstructure of the prepared surface. The contact angle was measured with DSA100 contact-angle meter. Chemical composition of surface, which was prepared on glass, was investigated using X-ray photoelectron spectroscopy (XPS).At the end of the study, the case, using THF as a solvent and glass as a coating substrate, superhydrophobic surface was obtained. The highest contact angle (153.6°) was measured for coating which involves 0.2g SiO2 at 140 °C drying temperature. The highest contact angle for cupper surface was found 141.0°. And the highest contact angle for glass surface which was prepared DMF as a solvent is 137.9°.