Construction And Anti-icing Performance Of Hierarchical NiCo₂O₄ Superhydrophobic Structure

The accumulation of ice on the surface of spacecraft,cable,communication equipment and vehicle has caused many inconveniences to the production and life of human being,and even caused major economic losses.Therefore,prevention of ice formation on the surface of materials have become a critical task need to be solved urgently.Nowadays,superhydrophobic materials have great applied potential in the field of anti-icing,due to water repellency properties of superhydrophobic materials.However,the stability of anti-icing property of superhydrophobic material is poor,which leads to the limitation of the application of the superhydrophobic material in the anti-icing field.In this paper,NiCo₂O₄ nanomaterials with porous structure were grown on the surface of foamed nickel.The superhydrophobic and anti-icingperformanceofmaterialwereachieved.Thestaticanddynamic superhydrophobicity and anti-icing performance of the material surface were studied.What's more,the mechanism of superhydrophobicity and anti-icing were investigated by a series of characterizations.Inspired by the water repellency property of super-hydrophobic surface,two composite superhydrophobic materials,NiCo₂O₄ nanoneedle/Ni foam and porous NiCo₂O₄ nanosheet/Ni foam,were constructed and compounded.The contact angle test showed that the apparent contact angle of two composite superhydrophobic materials were more than 160°.And water droplets could bounce off the surface of the composite superhydrophobic material around 8ms,indicating the composite superhydrophobic material has excellent water repellency property.The anti-icing performance of the composite superhydrophobic material was studied using the cooling controller and low-temperature test device.In the cold stage test,the delay time of NiCo₂O₄ nanoneedle/Ni foam and NiCo₂O₄ nanosheet/Ni foam were 5600 s and12600 s at-10?,respectively.The delay time of NiCo₂O₄ nanoneedle/Ni foam and NiCo₂O₄nanosheet/Ni foam were 840 s and 3840 s at-15?,respectively.In the low-temperature environmental test,delay time of NiCo₂O₄ nanoneedle/Ni foam and NiCo₂O₄ nanosheet/Ni foam reached 1.5 h and 5 h at-10?,respectively.The delay time of NiCo₂O₄ nanoneedle/Ni foam and NiCo₂O₄ nanosheet/Ni foam were 0.25 h and 1 h at-15?,respectively.This results show that two composite superhydrophobic materials exhibited good ice-retarding performance at low-temperatures,and NiCo₂O₄ nanosheet/Ni foam have superior ice-retarding performance.Then the dynamic behavior of water droplets was studied under low-temperature.This results show that water droplet can rebound off the superhydrophobic surface about 12 ms.And the bounce time was much smaller the delay time under the same temperature condition,which exhibitting a excellent anti-icing performance.The superhydrophobic and anti-icing mechanisms of two composite superhydrophobic materials were investigated by a series of characterizations?XRD,SEM,TEM,BET,XPS?.It is found that the microstructure of NiCo₂O₄/Ni foam had abundant porosity,and NiCo₂O₄nanomaterial had a large surface area,a large number of mesopores and much oxygen defects.These structural features benefit for trapping air in composite superhydrophobic material.The trap air reduced the free energy and heat transfer efficiency of the material surface.These make the composite superhydrophobic material have excellent hydrophobic and anti-icing performance.