Generation of stainless steel superhydrophobic surfaces using WEDM technique

This paper presents a novel fabrication methodology for generating superhydrophobic surfaces on stainless steel. The Wire Electric Discharge Machining (WEDM) technique was utilized to change the wettability of stainless steel which is generally hydrophilic. Superhydrophobic surfaces were obtained on the stainless steel by strictly control the machining progress. The mechanism of wettability modulation was explored using the well-established surface metrology and characterisation instruments. It was noted that WEDM can be used to generate a recast layer on stainless steel surface. There was a number of hierarchic micro-structures in the irregular recast layer and the number of micro-holes increases the contact area between the water drop and the top surface of stainless steel. Thus, the contact angle was significantly increased and the wettability of stainless steel changed from hydrophilic into hydrophobic. Compared with other established fabrication approaches, the stainless steel based hydrophobic surface can provide long durability, high efficiency and low cost metallic surfaces, which paves the way for the practical applications of stainless steel hydrophobic surfaces in the academic and engineering fields.