Preparation Of Bionic Foliar Structure Of Salvinia And Its Anti-fouling And Drag-reducing Performances

Marine biological fouling and ship resistance are two major problems that need to be solved urgently in the field of ships.They will bring about many hazards such as hull damage,increased fuel consumption.In particular,bionic superhydrophobic materials can form an insulating an air layer between material and water underwater,and have good antifouling and drag reduction properties.It has become a research hotspot in recent years.The leaves of Salvinia have good hydrophobic properties due to the fluffy structure on the surface.This paper chose to explore the leaf surface structure of Salvinia,and design the bionic Salvinia leaf surface structure.The bionic Salvinia leaf surface structure materials were prepared by 3D printing,and the methods of electrostatic flocking and electrodeposition modification were used to hydrophobically construct the bionic Salvinia leaf surface structure materials.The anti-fouling performance and drag reduction performance of the bionic Salvinia surface material were explored by using the typical fouling biological control test and the water adhesion and erosion drag reduction tests.The hairy structure on the leaf surface of four kinds of Salvinia,Salvinia natans,Salvinia minima,Salvinia spruce,Salvinia molesta are analyzed,and "eggbeater" and "claw" structures are designed.Two types of bionic structure materials were prepared using stereo lithography appearance 3D printing technology-the bionic Salvinia leaf surface "egg beater" type structure material(φ-SS)and the bionic Salvinia leaf surface "claw" type structure material(ψ-SS).The surface of the bionic Salvinia leaf structure material was modified by the method of highvoltage rising electrostatic flocking,and the hydrophobic surface from bionic Salvinia hydrophobic material with flocking multi-level structure(φ-ef-SS,ψ-ef-SS)was obtained.When it is underwater at a depth of 1 cm,the surface has an unstable air layer that can keep it from disappearing for 12 hours.The surface of the bionic Salvinia leaf structure material was modified by a combination of electroless copper-electrodeposited copper and chemical modification,and the superhydrophobic surface from bionic Salvinia hydrophobic material with electrodeposited multilayer structure(φ-ed-SS,ψ-ed-SS)was obtained.When the material is underwater at a depth of 1 cm,there is a relatively stable air layer on the surface of the material,and the air layer can be maintained for 36 hours without disappearing.Diatom attachment test,bovine serum protein attachment test,antibacterial property test,mussel attachment test were used to characterize the antifouling performance of the abovementioned materials.The bionic Salvinia hydrophobic material with flocking multi-level structure ef-SS have a certain inhibitory ability on common benthic diatoms,proteins,bacteria and other fouling organisms,and their inhibition rates are all above 75%;bionic Salvinia hydrophobic material with electrodeposited multilayer structure ed-SS have a strong static antifouling effect on common benthic diatoms,proteins,bacteria and other fouling organisms,and their inhibitory ability all are above 95%.The flow channel scouring test was used to test the pressure difference between the two ends of the bionic Salvinia leaf surface structure materials.The test found that the pressure drop of the bionic Salvinia leaf surface "claw" type structure material ψ-SS was stronger than that of the bionic Salvinia leaf surface "egg beater" type structure material ψ-SS.For the staggered ψ-SS material,when the flow rate is 6.5 m/s,the pressure drop capacity at both ends of the material can reach 68.04%,and when the flow rate is 2 m/s,the pressure drop capacity at both ends of the material is 93.02%.Adhesion test was carried out on the surface of the imitation Sophora japonicus surface material,and it was found that the surface adhesion force of the bionic Salvinia "claw" type surface material ψ-SS-above was lower than that of the bionic Salvinia "egg beater" type surface material φ-SS-above.The surface adhesion forces of bionic Salvinia hydrophobic material with electrodeposited multilayer structure φ-ed-SS and ψ-ed-SS are 69μN and 32 μN,which are less than that of the bionic Salvinia hydrophobic material with flocking multi-level structure φ-ef-SS and ψ-ef-SS,which are 72 μN and 38 μN.