New and Powerful Superhydrophobic Coating

A New and Robust Superhydrophobic Coating Inspired by lotus leaves, superhydrophobic coatings that resist wetting at their interface and exhibit unique multiphase contact properties have attracted researcher interest. However, fragile hierarchical structures, the use of fluorine-containing chemicals, and stringent requirements for substrate areas continue to pose challenges in this field. A research team led by Prof. Hou Baorong and Prof. Duan Jizhou from the Institute of Oceanology at the Chinese Academy of Sciences (IOCAS) recently announced that they have developed ZnO@STA@PDMS, a mechanically robust superhydrophobic coating using fluorine-free reagents via a substrate-independent spray coating method with broad application potential. The study was published in Materials & Design on 10 October. A hierarchical, rigid micro-scale bumpy porous structure, nano-scale particles, and the coating's extremely low surface energy contribute to water-repellent superhydrophobicity. The |Z|10mHz value of the coating, which becomes superhydrophobic immediately upon preparation, is three times higher than that of Q235 carbon steel. With the superhydrophobic ZnO@STA@PDMS coating applied via spray, the substrate's Icorr decreases by two orders of magnitude after coating, providing superior corrosion resistance performance. The prepared superhydrophobic coating can withstand more than 30 tape-peeling cycles and an abrasion distance of 400 cm, thus demonstrating good mechanical stability. Under simulated marine atmospheric conditions with high relative humidity, while recording hygroscopic and liquefaction movements of NaCl salt particles, an interesting spontaneous coalescence phenomenon was observed for the first time. The corrosion damage at the edge of the salt water droplet on bare Q235 carbon steel was more severe than in the interior due to faster ion transfer and high oxygen content. The superhydrophobic coating demonstrated promising atmospheric corrosion prevention performance based on salt dissolution and spontaneous coalescence phenomena. Low interfacial adhesion force, low surface energy, and Cassie multiphase contacts from air pockets contributed to the wetting-resistant performance of saline water droplets and corrosion prevention properties. Associate Professor Zhang Binbin, corresponding author of the study, stated: "This phenomenon provides a new corrosion prevention mechanism for superhydrophobic materials presented in marine atmospheric environments with high relative humidity."   Source More information: Binbin Zhang et al, Robust, scalable and fluorine-free superhydrophobic anti-corrosion coating with shielding functions in marine submerged and atmospheric zones, Materials & Design (2022). DOI: 10.1016/j.matdes.2022.111246 Provided by Chinese Academy of Sciences / https://phys.org/news/2022-10-robust-superhydrophobic-coating.html