| There are many superhydrophobic phenomena in nature,among which the microstructure of lotus leaf surface can make it "immaculate" has received much attention.Scholars have been inspired by observing and studying these interesting phenomena and successfully applied superhydrophobic surfaces in many fields such as industry and aerospace.In the laser etching process,the molten recast layer may affect the material surface properties and reduce the material surface hardness at the same time.While using laser with chemisorption method in the etching process,chemical reagents can react on the material surface,which improves the reaction rate,enhances the etching characteristics,improves the material surface hardness,and the recast layer phenomenon is significantly improved,which is beneficial to the application of superhydrophobic surfaces in practical engineering.In this paper,we adopt femtosecond laser etching and femtosecond laserassisted fluoride coating composite etching on 1A99 aluminum alloy surface to etch and prepare surface micro-nanostructures respectively,to study the changes of surface properties from the material surface micro-nano structures and compare the performance advantages and disadvantages of different hydrophobic surfaces in condensation and dust removal.The experimental contents and results are as follows.(1)The experiments were conducted using a femtosecond laser to ablate the sample surface,and then using a perfluorooctanol solution to reduce the surface energy of the sample,and finally the contact angle of the sample surface was measured with the help of a contact angle measuring instrument,and the measured values were used to characterize the hydrophobic properties of the sample surface.The results show that more excellent surface hydrophobicity can be obtained under the ablation effect of femtosecond laser with stronger laser pulse energy,lower laser scan speed and smaller scan spacing conditions.(2)The superhydrophobic surfaces were experimentally prepared by femtosecond laser under the conditions of lower scan speed,stronger laser pulse energy and smaller scan spacing using laser ablation in conjunction with fluorosilane modification,and the characterization properties of the prepared surfaces were studied.It was found that the superhydrophobic surface had a contact angle(WCA)of 152.8° and a roll angle(SA)of 0.6°,and the surface hardness was increased by 1.5 times compared with the aluminum alloy substrate,and the self-cleaning performance was significantly improved.The contact angle of the superhydrophobic surface decreased to 123° after 1500 mm wear,and still maintained a certain degree of hydrophobicity,showing better mechanical stability.(3)The effect of sample surface wettability on condensation and dust removal was experimentally investigated in a high humidity environment.It is shown that condensation and dust removal cannot be achieved on hydrophilic surfaces in the presence of condensate and that dust combined with condensate forms a fouling layer.The condensate droplets on hydrophobic and superhydrophobic surfaces clean up the dust by rolling,and the results,combined with the principle of force analysis,show that the dust removal performance increases with the increase of its surface contact angle when the droplets undergo movement.Figure [34] table [7] reference [97]... |
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