Facile Fabrication Of Super-hydrophobic Surface On Metal And Its Effects On Accelerating Underwater Bubble Bursting

Recently, super-hydrophobic surfaces have got wide applications in both fundamental research and practical application, and a facile fabrication of bio-mimic super-hydrophobic surfaces has attracted scientist’s attention. Meanwhile, a large amount of bubbles exist in the solutions, such as in the field of fibers fabrication. Since the bubbles can’t move from the spinning solution, the stability of the fibers can’t reach the global standards. In this study, we have developed three methods for the fabrication of super-hydrophobic surfaces:etching, electrochemical anodic oxidation and photolithography methods. The contact angel of water can reach155.9°without coating for any low energy materials. Furthermore, this study combines the super-hydrophobic surfaces and the bubbles in the solution, it shows a good way for the application of super-hydrophobic surfaces in inducing bubbles bursting. For different sized bubbles, the bursting time under a super-hydrophobic surface can shorten to about2/5to1/10comparing to freely bursting, which speeds up the bursting time significantly. The main results are as follows:(1) The super-hydrophobic surfaces we fabricated in this study have a combination of micro/nano hierarchical structures on metal. Moreover, we developed a simple one step etching method to fabricate a super-hydrophobic surface on aluminum surface, the etching solution contains HC1/SDBS. The fabrication process of this method is simple and easy to control, this intriguing effect may contribute to expand future fabrications and applications of super-hydrophobic surface in industrial field. Moreover, the surfaces can remain repellence after348days, which shows a good ability of weathering stability.(2) For untreated aluminum surface, when the bubbles contact with the surface, the bubbles bounce under the surface for several times and finally attach to the surface without bursting; however, for a super-hydrophobic surface, it can remarkably shorten the bursting time of air bubbles under water, and the bursting time is related to the size of the bubbles. If the size of bubbles is under lmm, the bursting time under super-hydrophobic surface can be shorten to about2/5, comparing to freely bursting, and if the size of bubbles is between1mm and8mm, the bursting time under super-hydrophobic surface can be shorten to about1/10. This mainly because there are a lot of micro free surfaces exist between the micro pillars and holes, when the film contacts with the micro free surface, it has a significantly deformation; meanwhile, the air pockets which exist between the micro pillars and holes can provide as a channel for the flow of the air from the bubbles. The gas can exhaust from the air pockets and burst at last.(3) The super-hydrophobic surface has an extremely property of collecting and adhering the bubbles in the solution. In this study, we have put the metal surface in a vertical way, the bubbles can attach to the super-hydrophobic surface, and even the pulling speed is400mm/min, the bubbles didn’t separate from the surface. The bubbles can only fly away from the metal with a violent shake. However, the bubbles can’t attach to the untreated Aluminum surface and the super-hydrophilic surface, which can be seen that the super-hydrophobic surface plays an important role in the collecting, adhering and removing of the bubbles in the solution.