*2.5. Surface Characterization*

The natural leaves, polished SS 316L plates and transferred plates from the three experimental groups were characterized by means of atomic force microscopy (AFM, Nanosurf Easyscan 2, Nanosurf AG, Liestal, Switzerland), to determine the surface roughness, and contact angle (CA) method to assess surface hydrophobicity. For AFM acquisition, a NCLR tip (Nanosensors™, Neuchâtel, Switzerland) in tapping mode at a constant force of 48 N/m was used. AFM images were processed using AxioVision software (V 4.9.1.0, Carl Zeiss Microscopy GmbH, Jena, Germany), Image J software (1.51 J, Laboratory for Optical and Computational Instrumentation, University of Winsconsin, Madison, WI, USA) [32] and WSxM software (5.0, Nanotec Electronic and New Microscopy Laboratory, Madrid, Spain) [33]. 10 AFM images of 50 × <sup>50</sup> <sup>μ</sup>m2 per group were used to obtain the arithmetic average of the roughness profile (Ra) using the Gwyddion software (2.34, Department of Nanometrology, Czech Metrology Institute, Brno, Czech Republic). For surface hydrophobicity, the sessile drop method was used on 10 plates from each group. A camera (Canon EOS Rebel XS, Tokyo, Japan) and a macro lens (105 mm F2.8 EX DG OS, Sigma, Ronkonkoma, NY, USA) were used to obtain the images and the angle values were obtained using software AxioVision (V. 4.9.1.0).
