Figure 1.
Characterization of the gradient surface. (a) Average Ra values along the gradient and its decomposition into components of different length scale (wavelength). (b–e) SEM micrographs of selected locations along the gradient. (b) Sandblasted area that did not undergo smoothing: note the abundance of sharp edges, ridges and peaks, Ra = 4.6 µm (unfiltered); (c) 2 mm into the gradient, Ra = 3 µm (unfiltered): note that the edges are rounded; (d) 5 mm into the gradient, Ra = 1.9 µm (unfiltered); (e) the smoothest part of the gradient, Ra = 0.9 µm (unfiltered).