Preparation Of Graphene Superhydrophobic Coating With Heat Resistance,Corrosion Resistance And High Strength

Superhydrophobicity has attracted the wide interest of many researchers,and new superhydrophobic materials have been developed and applied in many domains.For example,self-cleaning,anti-icing,oil-water separation,etc.However,there are still many key problems that need to be solved,such as poor heat resistance,low mechanical strength,weak chemical stability,which makes the corresponding superhydrophobic materials limited in practical applications.In the thesis,we proposed to prepare a high-performance graphene superhydrophobic coating based on a fiber reinforcement strategy using graphene as the main material.The main research contents and conclusions are as follows:1.Graphene oxide was prepared by the modified Hummers method,and graphene was obtained by the reduction of graphene oxide using hydrazine hydrate.The dispersion of graphene in different solvents was investigated,and the graphene coating was prepared by the drop coating method.The results show that graphene coating exhibits excellent superhydrophobicity with a water contact angle of 157.5° and a heat resistance of 240 °C.However,the mechanical strength of the coating needs to be improved.2.The mechanical strength of the coating was improved by introducing methyl silicone resin as a binder.By the thermal spraying method,superhydrophobic graphene coating combined with methyl silicone resin was prepared.The results show that the coating remained superhydrophobic after a wear distance of 6 m at a load of 100 g and its heat resistance reached 350 °C.3.To further improve the performances of the coating,a graphene composite superhydrophobic coating was prepared by introducing mullite fiber,graphene,methyl silicone,and ethanol to form a paint by the thermal spraying method,based on the principle of fiber reinforcement.The results show that the water contact angle of the coating surface remains above 150° after 150 days of immersion in various acid,alkali and salt solutions,reflecting the excellent corrosion resistance of the coating.The wear distance can reach 12 m under a 100 g load,indicating the high mechanical strength of the coating.The high temperature treatment and thermogravimetric test show that the coating still possesses superhydrophobicity after heat treatment at 350 °C for 10 h,and the thermal weight loss is only 10.17 wt% at 700 °C,which displays the coating has excellent heat resistance.4.The applications of the graphene composite superhydrophobic coating were investigated.The results show that the water contact angle of the coating exceedes 150°for six different liquids,such as PVA solution,sodium silicate solution,coffee solution,pure water,acid solution,and alkali solution.And the coating can strongly bond with different substrates,including ceramics,glass,plastic,fabric and metal,which indicates the superhydrophobic coating has a general usefulness.The icing time of the coating in the anti-icing experiment is 452 s,compared with that of the untreated surface,and the freezing time was delayed by 376 s,showing that the coating has excellent anti-icing performance.The coating is still superhydrophobic after 66 days of long-term outdoor exposure,displaying its long-term outdoor weather resistance.