Plasma processing is used to fabricate super hydrophilic or super hydrophobic polymeric surfaces by means of O2 plasma etching of two organic polymers, namely, poly(methyl methacrylate) (PMMA) and poly(ether ether ketone) (PEEK); a C4F8 plasma deposition follows O2 plasma etching, if surface hydrophobization is desired. We demonstrate high aspect ratio pillars with height ranging from 16 nm to several micrometers depending on the processing time, and contact angle (CA) close to 0 degrees after O2-plasma treatment or CA of 153 degrees (with CA hysteresis lower than 5 degrees) after fluorocarbon deposition. Super hydrophobic surfaces are robust and stable in time; in addition, aging of super hydrophilic surfaces is significantly retarded because of the beneficial effect of the nanotextured topography. The mechanisms responsible for the plasma-induced PMMA and PEEK surface nanotexturing are unveiled through intelligent experiments involving intentional modification of the reactor wall material and X-ray photoelectron spectroscopy, which is also used to study the surface chemical modification in the plasma. We prove that control of plasma nanotexture can be achieved by carefully choosing the reactor wall material.

We present an environmentally friendly, rapid, no-rinse and mass-production amenable plasma process for the fabrication of super-hydrophobic (SH) poly(methyl methacrylate) (PMMA) surfaces using only a one load/unload step in a low-pressure, high-density plasma reactor. First, oxygen plasma is applied to nanotexture the PMMA surface via etching processes leading to high aspect ratio (HAR) topography, with dual-roughness characteristics for short process durations, as evidenced by AFM analysis. The duration of the process may range from 1 min to several min depending on the roughness amplitude and on the degree of transparency desired. The significance of the ion-bombardment is revealed and discussed. After this first step, the gas chemistry is changed to a fluorocarbon one which leads to a few nanometres-thick Teflon-like film deposition, thus altering the PMMA surface chemistry within a few seconds. Following this process, a very large area (depending on the reactor scale) of the PMMA may become SH in less than 1.5 min (total process duration) with a transparency as desired (from fully transparent to milky and antireflective). The contact angles (CA) measured are approximately 152° with 5° hysteresis. For short process durations, the dual-roughness character of PMMA surfaces favours the SH formation, despite the low roughness factor. Furthermore, the dry and low-temperature character of the process ensures the intactness of PMMA’s shape and bulk mechanical properties.

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