Wire Electrochemical Machining of Multiscale Superhydrophobic Arrays with Specific Unit Shapes on Stainless Steel.

The multiscale superhydrophobic array with a specific unit shape has a broader prospect for application in engineering materials, such as stainless steel (SS). However, the fabrication of the multiscale superhydrophobic array with a specific unit shape remains limited by several aspects, mainly including the complexity and controllability of multiscale integration of microstructures and arrays, the difficulties in obtaining specific unit shapes, and the low safety. Therefore, there is an urgent need for a relatively controllable, simple, and safe method to achieve a multiscale superhydrophobic array with a specific unit shape. Here, a safe and controllable method of integrating the array and microstructure into a multiscale superhydrophobic array is proposed by only wire electrochemical machining (WECM) in a harmless neutral electrolyte with controllable construction of different unit shapes. Here, first, the simulation and experiment of unit shapes by WECM is conducted to reduce the complexity of selecting parameters for different unit shapes; then, an integration of the microstructure and array is conducted; finally, hydrophobicity performances of multiscale superhydrophobic arrays are tested, including the drop loading test and drop impact test. The results show that multiscale superhydrophobic arrays by WECM exhibit excellent anti-intrusion performance and reduce solid-liquid contact time significantly, indicating only WECM can construct multiscale superhydrophobic arrays on SS with good controllability and safety.