Bionic Fabrication And Properties Of Superhydrophobic Copper Surfaces

Based on the researches and analysis of the superhydrophobic surface in nature,the researchers used a variety of methods to prepare artificial superhydrophobic surface,such as template method,sol-gel method,corrosion method and so on.Metal is the most widely used engineering material,and superhydrophobic materials with metal substrates also have a broad application prospects.Therefore,the preparation and research of superhydrophobic materials with metal substrates are very significant.In this paper,regarding rice leaves as bionic objects,we use the method combine mechanical etching with electrical brush plating to build a multi-level hierarchical structure of rice leaf structure on the copper substrate.And then after the chemical modification,the prepared copper film surfaces behave superhydrophobic properties.We used scanning electron microscopy,X-ray photoelectron spectroscopy,optical contact angle measuring instrument and other equipment to characterize the copper films,We also study the application properties of superhydrophobic copper film surfaces,such as anti-icing,self-cleaning,durability,etc.The main work we have done is shown below:(1)Regarding rice leaves as bionic objects,we use the method combine mechanical etching with electrical brush plating,controling the voltage,current density,moving speed,plating time and other parameters,to build a multi-level hierarchical structure similar to rice leaf structure on the copper substrate.The microstructure consists of a micron-scale periodic groove array,a sub-micron cluster structure and a large number of nanocrystalline blocks.A superhydrophobic copper film with wetting anisotropy was prepared by low surface energy modification.The maximum static contact angle of the droplet on the copper film surface is 161.4° and the minimum rolling angle is 3.5°.In addition,due to the presence of periodic groove array,the copper film surface exhibits anisotropic wettability,and the static contact angle measuring from the direction parallel to groove is different with the vertical direction,and the maximum anisotropy reaches 8.7°.(2)By controlling the other brush plating process parameters,we prepared a series of super-hydrophobic copper films under different plating time.The change of the process parameters resulted in different microstructure of the material surface,which affected the wetting properties of the copper film surface.We investigated the effects of different groove heights on the static wetting behavior and dynamic wetting behavior and wetting anisotropy of the copper film surface.The results show: with the increase of the groove height,the contact angle measuring from the direction parallel to the groove increases;while the rolling angle and the dynamic contact angle hysteresis decreases.The contact angle,the rolling angle and the contact angle hysteresis measuring from the direction perpendicular to groove are nearly unchanged.The anisotropy of the contact angle increases,and the anisotropy of the rolling angle and the contact angle hysteresis decrease.(3)We conducted a series of tests on the superhydrophobic copper film,including self-cleaning test,droplet bounce test,durability test,and anti-icing test.The results show that the surface of super-hydrophobic copper film has excellent properties of self-cleaning,low adhesion,mechanical friction resistance and anti-icing.The prepared superhydrophobic copper films have high practical application value and application prospect.