Preparation Of Superhydrophobic Surface Based On Electrostatic Spray

Superhydrophobic materials have shown great application potential in oil-water separation,anti-icing and other aspects because of their unique surface wettability.However,there are many problems in the preparation of superhydrophobic surface,such as complex preparation process,high cost,strong corrosion of reagents,narrow scope of application.In this paper,a new method for preparing super hydrophobic surface based on electrostatic spray technology was proposed.The method was explored through theoretical analysis and experimental research,and the main contents include the following points:(1)The superhydrophobic theory and electrostatic spray mechanism were studied.Four models of liquid and interface were analyzed.The charge mass ratio of liquid drop charged by induced charge and the capacity of ring electrode capacitor charged by contact charge were calculated by Gauss theorem.The relationship between jet state and voltage was tested by experiments.The volume force and surface force of charged liquid jet in electric field were analyzed;the breakup of charged droplets in electric field was analyzed based on Rayleigh Limit.(2)The method of preparing super hydrophobic surface by electrostatic spray technology was studied though principle and experiment.The principle of electrostatic spray for preparing superhydrophobic surfaces was introduced though surface microstructures,low surface energy and silica properties.The influence of electrostatic spray voltage and time,and the size of silica particles on the surface morphology and wettability were discussed by means of controlled variable method.Superhydrophobic stainless steel mesh,copper mesh and acrylic mesh were prerared,showing that the method had wide applicability The superhydrophobic meshes were immersed in different p H electrolyte solutions,which verified the chemical stability of superhydrophobic meshes.Compared with the spray gun method and immersion method,founding that the surface microstructural uniformity and density of meshes made electrostatic spray were better.(3)The oil-water separation performance of superhydrophobic mesh was tested.The feasibility of oil-water separation of superhydrophobic mesh was verified though the wettability of oil and water to superhydrophobic mesh,and the water pressure resistance of superhydrophobic mesh.The wettability of oil and water to superhydrophobic mesh was tested by contact angle,liquid drop bounce and liquid infiltration.The water resistance of superhydrophobic mesh was tested,and the water pressure supported by the superhydrophobic meshes was about two times of that of the untreated stainless steel meshes.What’s more,it is proved that the superhydrophobic meshes still had good waterproof performance after a long time of oil flow.The superhydrophobic meshes were used to collect the floating oil,and the excellent oilwater separation performance of the superhydrophobic meshes was proved from four aspects: collection rate,environmental adaptability,oil-water separation purity and recycling performance.(4)The wear-resistant superhydrophobic coating was prepared and its anti-icing performance was tested.The adhesive was added between the slide and silica to improve the wear resistance.Grinded the coating with different sandpaper,the change of contact angle of the coating was within 7 °,indicating that the coating was wearresistant.Tested the frosting rate of the slides before and after treatment under supercooling condition,and the results showed that the superhydrophobic coating could delay frost formation in the early stage.Compared the impact phenomenon of the water drop and the slides before and after treatment,proving that the superhydrophobic coating had anti ice property.