Preparation And Properties Of Hydrophobic Coatings Based On Modified Graphene Oxide

Superhydrophobic coatings have been intensively used in various fields due to special infiltration of their surfaces,such as self-cleaning,anticorrosion,anti-fouling and oil/water separation.In this paper,novel superhydrophobic coatings based on hydrophobic material(ODA-GO)were prepared by spraying and leaching methods.Then ODA-GO/PU composite hydrophobic coatings with high wear-resistance and hydrophobicity were fabricated by spraying after physical blending.The structure and properties of the ODA-GO and(super)hydrophobic coatings were further analyzed.(1)GO was prepared by improved Hummers method,using long-chain alkanes contained in octadecylamine(ODA)to hydrophobically modify GO.The structure of the resultant ODA-GO was characterized by Fourier infrared spectrometer(FTIR),thermogravimetric analyzer(TG),X-ray diffraction(XRD)and Raman spectroscopy.The results showed that GO contained a lot of oxygen-containing functional groups.Upon modification with ODA,ODA-GO exhibited characteristic absorption peaks of long-chain alkanes,interplanar spacing increased by 1.65 nm and the trend of thermal weight loss of ODA-GO became flattened.Atomic force microscopy(AFM),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and super-depth of field microscopy were used to observe morphology of ODA-GO.The results showed that the surface of GO sheet was wrinkled with strong hydrophilicity.The microscopic roughness of ODA-GO was increased significantly and hydrophobic performance was increased with the augment of ODA.The ODA-GO power was superhydrophobic.(2)ODA-GO was dispersed in different solvents and acetone was determined as a good solvent at length.The coatings were prepared by spraying ODA-GO dispersion and characterized by SEM,contact angle meter and super-depth of field microscopy.The results showed that GO coating had a high degree of microflatness and good hydrophilicity,water contact angle(CA)was 25.3°.The roughness of ODA-GO coatings increased obviously,when the mass ratio of GO and ODA was 1?5,CA of ODA-GO coating was 151.2°,rolling angle(SA)was less than 6° with superhydrophobicity.Corrosion resistance,ultraviolet(UV)resistance and self-healing properties of ODA-GO superhydrophobic coatings were examined.The studies found that CA of the coating changed within 6° after corrosion and the coating after 2000 min UV radiation still had good chemical stability,CA remained above 150°.The coatings had good UV light and chemical stability.CA of coating prepared by filtering ODA-GO dispersion in acetone reached 162.9° and SA<3°.The study on self-repairing properties of filtering coating found that the coating was transformed into hydrophilicity by plasma etching,superhydrophobic property was re-reached after heating treatment.(3)Blended ODA-GO with polyurethane(PU),then sprayed to prepare ODA-GO/PU hydrophobic composite coating.The results of SEM,super-depth of field microscopy and contact angle test showed that surface roughness of composite coatings decreased with increase of PU and CA of composite coating decreased to 116.8°.Friction resistance results of composite coatings showed that PU was beneficial to improve mechanical properties.CA reached 156° and the composite coating was superhydrophobic after friction.The results of corrosion resistance and UV resistance of composite coatings showed that the composite coatings had good UV resistance but acid and alkaline solution had a greater influence on the surface wettability.(4)The ODA-GO acetone dispersion was sprayed on market copper to prepare a superhydrophobic copper which can be applied to the oil and water separation system.SEM,contact angle tests and super-depth of field microscopy results showed that layer structure of superhydrophobic copper surface was obvious and roughness was increased.CA of superhydrophobic copper was 159.7° and oil(toluene)spreading rapidly.Water pressure resistance test of superhydrophobic copper and stripping resistance results showed that the maximum pressure of superhydrophobic copper was 0.6 Pa and the superhydrophobic surface after stripping 10 times still had good high hydrophobicity performance.Stripping resistance of superhydrophobic copper was good.The results of oil and water separation tests showed that separation efficiency of superhydrophobic copper can reach 99% and had cyclic usability.