Electrohydrodynamic behavior of water droplets on a horizontal super hydrophobic surface and its self-cleaning application

• Published in: Applied surface science 2017-05, Vol.403, p.133-140
• Main Authors: Li, Jian, Wei, Yuan, Huang, Zhengyong, Wang, Feipeng, Yan, Xinzhu, Wu, Zhuolin
• Format: Article
• Language: English
• Subjects: Electrohydrodynamic behavior of water droplets; Micro/nano hierarchical structure; RTV silicone rubber; Self-cleaning; Superhydrophobicity
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2017.01.141

•A simple process to fabricate super hydrophobic surface based on nano size silica particles and perfluoroalkyl methacrylic copolymer.•The super hydrophobic exhibits coral-like hierarchical surface structure with a water contact angle of 160.4±2° and slide angle less than 1°.•Water droplets on a horizontal super hydrophobic surface were able to proceed a self-propelled motion driven by electric field.•The motion of the droplets could automatically take away contaminants, which provided the feasibility for anti-pollution application. Moisture is a significant factor that affects the insulation performance of outdoor high-voltage insulators in power systems. Accumulation of water droplets on insulators causes severe problems such as flashover of insulators and power outage. In this study, we develop a method to fabricate a micro/nano hierarchical super hydrophobic surface. The as-prepared super hydrophobic surface exhibits a water contact angle (WCA) of 160.4±2°, slide angle (SA) less than 1° and surface free energy (SFE) of 5.99mJ/m2. We investigated the electrohydropdynamic behavior of water droplet on a horizontal super hydrophobic surface compared with hydrophobic RTV silicone rubber surface which was widely used as anti-pollution coating or shed material of composite insulator. Results show that water droplet tended to a self-propelled motion on the super hydrophobic surface while it tended to elongate and break up on the RTV surface. The micro/nano hierarchical surface structure and chemical components with low surface free energy of the super hydrophobic surface jointly contributed to the reduction of skin fraction drag and subsequently made it possible for the motion of water droplet driven by electric field. Furthermore, the self-propelled motion of water droplets could also sweep away contaminations along its moving trace, which provides super hydrophobic surface a promising anti-pollution prospect in power systems.