Non-stick cookware has long relied on PTFE as the coating layer despite its potential health and environmental hazard. Here, we explore an alternative method to render stainless steel non-sticky without the use of PTFE. The method applies electrochemical etching in an ionic liquid electrolyte to create multiple scales of roughness on the steel surface, which displays a large wetting angle and thus hydrophobicity. We reveal how the etched structure depends on the electrolyte composition and the electrochemical potential, and thereby design a rapid, consistent process of fabrication. Characterization methods, including atomic force microscopy, optical profiling, and electron microscopy, show that the microstructure comprises micron-sized pits and nanometer-wide pores. The seemingly fracta...[ Read more ]

Non-stick cookware has long relied on PTFE as the coating layer despite its potential health and environmental hazard. Here, we explore an alternative method to render stainless steel non-sticky without the use of PTFE. The method applies electrochemical etching in an ionic liquid electrolyte to create multiple scales of roughness on the steel surface, which displays a large wetting angle and thus hydrophobicity. We reveal how the etched structure depends on the electrolyte composition and the electrochemical potential, and thereby design a rapid, consistent process of fabrication. Characterization methods, including atomic force microscopy, optical profiling, and electron microscopy, show that the microstructure comprises micron-sized pits and nanometer-wide pores. The seemingly fractal surface can trap air upon its contact with liquid and thus weakens its adhesion. The non-sticking property of the etched stainless steel is confirmed by milk tests; burnt milk can be released from its surface for at more than five times. The results reveal general structural dependence of non-stick properties that can be applied to other materials.