Influence Of Micro-structure On Al Surface Superhydrophobicity

Superhydrophobic surface(SHS) has widely application prospect in everyday life, industrial manufacture and other fields for its properties like self-cleaning, ice-restrain caused by outstanding hydrophobicity. Researches show that this special wettability can be attained by controlling surface free energy and surface micro-structure. Along with the development of SHS, numbers of methods to fabricate SHS have been reported in recent years. However, these methods can hardly guarantee the consistence of surface micro-structure. As to metal substrate, machining is the common method to fabricate consistent micro-structure while this micrometer-scale machining has strict requirements for process and equipment especially on soft metal like Aluminum. As a result, there are few reports about the influence of surface micro-structure on Aluminum surface hydrophobicity. Therefore, the research goal of analyzing influence of surface micro-structure on Aluminum surface hydrophobicity was proposed.In this work, micro-structures includes micro-pillar, micro-pit and micro-groove have been designed according to classical super-hydrophobicity theories and reported SHS’ micro-structure. The influence of micro-structure’s morphology and size on surface contact angle have been discussed and equation to calculate contact angel also has been deduced according to surface wettability theories and contact angel modles. Through-mask electrochemical micromachining (TMEMM) was applied in this work to fabricate micro-structure surface on Aluminum substrate. Consistent micro-structure surface on Aluminum substrate can be attained through TMEMM, and experimental result shows morphology and size of micro-structure can be controlled by changing process parameters.Through observing the contact form of water droplet and measuring of contact angle, the influence of micro-structure’s morphology and size on contact angle and contact form of water droplet can be analyzed, and the experimental results well fit the theory prediction.