Towards super-nonstick aluminized steel surfaces

Abstract One of the main challenges in cookware and baking industry is the fabrication of enhanced nonstick coatings including two main features: highly hydrophobic, resistant and durable. In general, life-long release coatings are prepared with a polymer-filler composite of several microns thickness deposited on food-compatible metals such as aluminum, stainless steel or aluminized steel, as the dimensions and functionality of the product. In this work we present several routes to fabricate water-repellent surfaces on aluminized steel as alternative to current nonstick coatings but with enhanced release properties and high durability. For this purpose, we explored two different strategies to directly create hierarchical texture on aluminized steel surfaces: sandblasting in combination to acid etching and single acid etching. The rough metal surfaces were further hydrophobized by using two different organic coatings: a Teflon film and a silane monolayer. The release properties were quantified through the study of the adhesion of water drops by means of sliding angle and contact angle measurements. We identified the most appropriate texturing process by assessing a balance between the water repellency properties and the lowest damage caused on the metal surface. This damage was quantified through thickness loss measurements of the aluminum layer. The durability of the samples was analyzed with Scotch-peeling test and next, with sliding angle measurements. We analyzed the roughness and morphology of the surface textures by contact profilometry and FE-SEM. The surface chemical composition was also analyzed by EDX. Our results pointed out to that the most durable repellent surfaces were those ones silanized. The combination of sandblasting and acid etching and the hydrophobization process with silane molecules enable to fabricate super-nonstick coatings on aluminized steel of high durability.