Fabrication Of Superhydrophobic Coating Based On Morphology Control Technology And Its Application In Oil-water Separation

Superhydrophobic surfaces have potential application value in the fields of anti-corrosion,anti-icing,drag reduction,oil-water separation and self-cleaning due to its excellent performance.However,most of the superhydrophobic surfaces fabricated at present are limited by the poor adhesion and short duration of superhydrophobicity and are difficult to popularize and apply in large areas.This work was inspired by high-adhesion coatings and the superhydrophobic coatings were prepared on the basis of morphology control technology.This method is simple to perform,and the superhydrophobic surfaces has strong adhesion.The main research conclusions are as follows:1.Basic principles,fabrication methods,application fields,existing problems and development trends of superhydrophobic surfaces were reviewed on the basis of consulting a large number of literatures.2.Modification of nano SiO₂.The hydrophilic nano SiO₂ was modified with?-aminopropyltriethoxysilane?KH550?.The modified nano SiO₂ was characterized using Fourier transform infrared spectrometer?FT-IR?,X-ray diffractometer?XRD?,scanning electron microscope?SEM?and contact angle meter,and the oleophilicity of the modified nano SiO₂was calculated and the modification principle was analyzed.The results showed that the modified nano SiO₂ was amorphous,the particle size was about 50 nm,the water contact angle?WCA?was 134.5°and the lipophilic value was 49.6%.KH550 successfully modified hydrophilic nano SiO₂ to hydrophobic nano SiO₂.3.Fabrication and performance of superhydrophobic coatings.Using suitable material as filler and tridecafluorooctyltriethoxysilane?G617?as low surface energy material,superhydrophobic coating A was fabricated using fluorocarbon varnish as film-forming substance and superhydrophobic coating B was fabricated using silicon-containing polytetrafluoroethylene as film-forming substance by brushing method.The optimal conditions for fabricating superhydrophobic coating was studied and the thickness,hardness,adhesion force,acid and alkali resistance,self-cleaning performance and corrosion resistance of two superhydrophobic coatings were also tested.The results showed that the optimal filler for superhydrophobic coating A and B was hydrophobic nano SiO₂,the optimal content of filler was 19%and 15%respectively,the optimal content of G617 was 2%and 1%respectively,the optimal stirring time was 20 min and 30 min respectively,the maximum value of WCA was152°and 153.5°respectively.The coating thickness was 26?m and 22?m respectively.The coating hardness was H and 4H respectively.Shedding occurred at 40 min and 1 h respectively in 10%H₂SO₄ solution and shedding occurred at 90 min and 2 h respectively in 10%NaOH solution.The two superhydrophobic coatings both had self-cleaning performance.The two superhydrophobic coatings both had anti-corrosion performance at the initial stage in 3.5%NaCl aqueous solution,and superhydrophobic coating A had lost anti-corrosion performance while superhydrophobic coating B still had anti-corrosion performance but was greatly weakened after 96 h.4.The outdoor testing of superhydrophobic coatings.The 238-day natural climatic exposure test was carried out and artificial rainfall was simulated on the 0th,7th,14th,49th,105th,and 238th days.The results showed that the hydrophobicity of the superhydrophobic coatings A and B decreased with the increasing of the atmospheric exposure time.70%of the surface of superhydrophobic coating A showed rust at the end of the test,the WCA of the rusted part was 34.5°,and the WCA of the unrusted part was 137°,which maintained hydrophobic property.The surface of superhydrophobic coating B was completely rusted at the end of the test,the WCA was 24.5°and the hydrophobic property was lost.5.The application of superhydrophobic coating in oil-water separation.Superhydrophobic coatings A and B could be recycled for heavy oil/water separation multiple times.The separation efficiency of superhydrophobic coating A decreased from 96%to 84%after recycling for 10 times with low repeat utilization.The separation efficiency of superhydrophobic coating B was still above 99%after recycling for 50 times with high separation efficiency and repeat utilization,and the oil content in water had almost no effect on the separation efficiency of superhydrophobic coatings A and B.