Atmospheric Plasma Nanotexturing of Organic–Inorganic Nanocomposite Coatings for Multifunctional Surface Fabrication

We present the concept of the combined synthesis of organic–inorganic nanocomposite coatings and atmospheric pressure plasma etching/nanotexturing for tailoring the surface topography and fabricating multifunctional surfaces. As demonstration, we fabricated superhydrophobic ZnO/poly(methyl methacrylate) (PMMA) nanocomposite coatings. Composite coatings differing in ZnO content were synthesized and plasma etched in a dielectric barrier discharge operating in He/O2 in an open-air environment. The phase selective plasma etching of organic over inorganic matter resulted in the gradual revealing of the inorganic ZnO particles, which were multisized due to agglomeration during the synthesis and plasma etching process. The creation of hierarchical topography led to the fabrication of roll-off superhydrophobic surfaces with water contact angle ∼158° and sliding angle ∼3° after the application of a low-pressure plasma deposited Teflon-like film. Moreover, we studied the optical properties of the superhydrophobic, atmospheric plasma nanotextured surfaces in terms of reflectance measurements (total, diffuse, and specular) to evaluate their possible use as antireflective surfaces.