ABSTRACT
Superhydrophilic and superhydrophobic surfaces have achieved incredible interest from scientific communities and industries due to their fascinating wetting properties. Various different techniques have already been developed for the fabrication of these surfaces individually. However, synthesis of these surfaces by the highly sophisticated technique as well as multiple steps limit them only to the lab scale. Moreover, majority of these approaches involves the use of polymeric surfaces which have certain limitations in harsh environment. We demonstrate a one-step and simple scalable technique to instantly tune all the different states of wetting using atmospheric plasma spray (APS) technique. Our findings indicate that wetting characteristics of an intrinsically hydrophilic metallic surface can be tailored to superhydrophilic (CA: 0°), hydrophilic (CA: 19.6°), hydrophobic (CA: 97.6°) and superhydrophobic (CA: 156.5°) surfaces just by changing the process parameters in APS technique. Also, an excellent self-cleaning property was observed in the superhydrophobic surface. In addition, we showed that these surfaces preserve their superhydrophobic nature even after exposing at elevated temperatures (up to 773 K) and on application of mechanical abrasion. Tailoring the different wetting behaviors was possible primarily due to the multi-scale roughness as a result of smooth surface as well as micropillars over the surface.
