Novel Hollow Re-entrant Structures Improving Hydrophobicity of Metal Surfaces

Re-entrant structures have drawn increasing attention because of their hydrophobicity.However,it is very difficult to manufacture re-entrant structures at the micron scale on metal surfaces.In this study,we designed and manufactured novel hollow re-entrant structures employing laser ablation and electrodeposition technology.This designed hollow re-entrant structure on metal surfaces has been fabricated successfully,which has high processing efficiency and good repeatability.The morphology and size of the hollow re-entrant structures were characterized.We found that the hydrophobic performance of hollow re-entrant structures was improved after being in the atmosphere for 3 days.After electrodeposition,the static contact angle was 133°.However,after being placed in the atmosphere for 3 days,the static contact angle was 140.4°,which is 5.2%higher than that after electrochemical deposition.We explained the cause of this phenomenon.The change of element content on the surface of hollow re-entrant structures was used to indicate the formation of metal oxide.After being in the atmosphere for 3 days,oxygen content increased by 0.4%.The metal surfaces with hollow re-entrant structures have a broader application prospect.