Preparation And Properties Of Low Surface Energy Resin-based SiO₂ Nanocomposite Superhydrophobic Coatings

Due to their unique properties,superhydrophobic materials can have practical applications in many fields,such as anti-icing of transmission lines,anti-corrosion of metal surfaces and anti-biosorption of ships,which has led researchers to conduct research.The industrialisation of superhydrophobic coatings has been severely limited by the complexity of the preparation method and poor mechanical durability.In this thesis,superhydrophobic coatings were prepared on stainless steel sheets using a simple spray method dedicated to improving the mechanical durability of the coatings,using different low surface energy resins as binders and modified silica to provide micro-nano protrusions.The effect of different binder layers on the performance of the superhydrophobic coatings was also investigated separately.The main findings of this thesis are as follows:1.Polydimethylsiloxane（PDMS）/Si O₂ superhydrophobic coatings were prepared using a one-step spraying method.The hydrophobic silica was first modified with perfluorodecyltriethoxysilane（PFDTES）with a particle size of 30 nm before spraying.The effect of different levels of modified Si O₂ on the wettability of the coating was investigated.The results showed that when the content of modified Si O₂ reached 0.5 g,the modified particles and the low surface energy resin bonded well and the coating obtained the best superhydrophobic properties with a contact angle of 154.1°and a rolling angle of 5.52°.The coating exhibited excellent corrosion resistance,chemical stability and self-cleaning properties.The contact angle of the sample was 146.73°after 10 wear cycles in the wear test.However,in the tape peel test,the surface micro-nano structure of the coating was severely damaged after 2 peel cycles.2.Epoxy resin（EP）/PDMS/Si O₂ superhydrophobic coatings were prepared by a two-step spraying method.The effect of different EP contents on the wettability of the samples was investigated.The results showed that the best crosslinking between the bonding layer and the superhydrophobic coating was achieved when the EP content was 2.6 g.The contact and rolling angles were 151.22°and 7.85°respectively,and the coating obtained the best superhydrophobicity with increased mechanical stability.The samples were still able to reach a contact angle of 151.43°after 10 wears and had a contact angle of 151.12 after 9 peels°.In addition the EP/PDMS/Si O₂ superhydrophobic coating shows excellent chemical stability and self-cleaning properties.3.Polystyrene（PS）/Si O₂ superhydrophobic coatings that can be cured at room temperature were prepared by a one-step spraying method.The effect of different PS contents on the mechanical properties of the samples was investigated.The results show that the interaction between PS and modified Si O₂ particles is optimal when the PS content is 0.6 g.A good balance between adhesion to the substrate and superhydrophobicity is achieved with a contact angle of 157.9°and a rolling angle of 0.84°.The contact angle was around 150°after 10 wears and 155.43°after 10 tape peels.The prepared coating can withstand the impact of a water stream with a Weber number of 1902.Moreover,the PS/Si O₂ superhydrophobic coating prepared by this method is universal,chemically stable,self-cleaning and corrosion resistant.