Study On Surface Microstructures Of Metallic Anisotropic Wettability Prepared By Laser Texturing

The anisotropic super-wetting surface has special properties such as directional liquid transport and water droplet adhesion,and has important applications in the fields of mist collection,cell engineering,and drug supply.Laser processing has the characteristics of high processing accuracy,easy use,and wide selection of materials.In this paper,a laser etching technique is used to design and prepare an anisotropic superwetting surface on a metal surface.The realization mechanism and control method of the anisotropy are discussed.The main research work as follows:1.Designed an asymmetric multi-directional stairway(AMDS)microstructure,which was prepared on the surface of aluminum alloy by layer-by-layer etching method with precise laser selection,and realized the droplets in four directions.Anisotropic adhesion is super-hydrophobic.On a 7-step AMDS microstructure surface,the sliding angles(SA)of the droplets in the four directions are 8 ° 17.2 °,21.5 °,and 35.5 °.The realization mechanism of the anisotropy is revealed,which is the result of the combined effect of the resistance effect and the adhesion force caused by the stepped slope.In addition,through the special arrangement of AMDS microstructures,a microfluidic surface case was designed to achieve the orderly rolling of droplets on the surface.2.A superhydrophobic/superhydrophilic composite microstructured surface was designed and prepared on the surface of magnesium alloy by two laser scanning methods.The water contact angle(WCA)of the surface in the superhydrophobic region and the air contact angle(ACA)in the water of the superhydrophilic region both reached 154°,which has the ability to capture bubbles by underwater patterning.a stripe pattern is designed on the surface,and strip-shaped bubbles can be captured in the water.Anisotropic flow resistance characteristics caused by bubbles in the flow field were realized.By adjusting the arrangement direction of the superhydrophobic/superhydrophilic stripes on the sample surface,the attitude control of the floating sample in the flow field environment was finally achieved.In addition,it explains that the mechanism is mainly the transition of superhydrophobic and superhydrophilic surfaces under water to superaerobic and superaerobic surfaces under water,and the regulating effect of bubble pattern on the flow resistance.