Thesis Type: Postgraduate
Institution Of The Thesis: Kocaeli University, Fen Bilimleri Enstitüsü, Havacılık Bilimi ve Teknolojileri Böl., Turkey
Approval Date: 2021
Thesis Language: Turkish
Student: ALİ HAYDAR GÜNEŞ
Supervisor: Sinan FidanAbstract:
Many species in nature show superhydrophobic properties, and the low-energy biological surfaces of these species with micro-nano hierarchical structures have inspired the development of superhydrophobic surfaces. Today, although superhydrophobic surfaces can be produced using many methods, these human-made surfaces cannot maintain their water repellency feature for a long time under outdoor conditions. In this study, superhydrophobic surfaces were produced using two different polymers, epoxy and polyurethane, and hydrophobic fumed SiO2 (silica) nanoparticles.The resulting surfaces were characterized by measuring the three-dimensional non-contact profilometer and the static water contact and sliding angle shift.Although water contact angles of more than 150 degrees can be obtained on polyurethane surfaces, superhydrophobicity cannot be achieved, while most epoxy coatings show superhydrophobic properties. Two different mechanical durability tests have been used to examine the usability of the produced surfaces in outdoor conditions The impact resistance of the surfaces was examined by the sand impact durability test and the abrasive wear resistance by the linear abrasion stability test. The wettability and mechanical durability of the surfaces differ significantly depending on the production parameters. These parameters are: (i) the production method selected according to the polymer type, (ii) the siloxane type used to modify the surface energy of the epoxy, (iii) the amount of siloxane, (iv) the number of nanoparticles, and (v) the spraying time. Epoxy / Polydimethylsiloxane / SiO2 surfaces containing certain amounts of polydimethylsiloxane and SiO2 nanoparticles exhibit superior wettability and mechanical durability properties. Another important result obtained is; Spraying time plays an important role in the mechanical wear behavior of surfaces. Coatings with short spraying time exhibit high abrasive wear resistance. Coatings produced with a long spraying time retain their water repellency properties for a long time under dynamic impacts.