Hierarchical micro-nanostructured surfaces are key components of 'smart' multifunctional materials, used to control wetting, adhesion, tactile, friction, optical, antifogging, antibacterial, and many more surface properties. Hierarchical surfaces comprise random or ordered structures ranked by their length scale spanning the range from a few nanometers to a few micrometers, with the larger microstructures typically embedding smaller nanostructures. Despite the importance of hierarchical surfaces, there have been few studies on their precise and controlled fabrication or their quantitative characterization, and they usually involve multiple and complex fabrication steps. Here, we present a new plasma nanotechnology, which we term 'nanoinhibit', and a new plasma reactor for producing in one facile process-step-controlled hierarchy at will on polymeric surfaces. We couple the new plasma nanotechnology with detailed computational nanometrology based on the analysis of scanning electron microscopy images and targeted to specific functionality. We showcase the potential of 'nanoinhibit' for functional surface fabrication by controlling the wetting and optical functionality of the fabricated hierarchical surfaces and showing its dependence on surface morphology metrics. Finally, we observe that 'nanoinhibit' produces a new class of 'strong hierarchical' surfaces exhibiting spatially separated periodic and fractal-like components.
Keywords: controlled nanofabrication; hierarchical surfaces; multifunctional materials; nanometrology; nanopatterning; plasma nanotechnology.
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