In this paper, we report on a continuous, flexible, and transparent graphene film obtained by cold wall chemical vapor deposition (CVD) on Cu foil. The good continuity of the graphene film, obtained in optimized conditions (e.g., pretreatment to increase copper grain size, Ar flow during synthesis to control Cu sublimation) was successfully transferred on a PET substrate to be applied with a double function of window electrode and barrier film. PET film after a single layer graphene deposition showed good performance: a sheet resistance of 0.6 kΩ/sq, a low reduction of transmittance in comparison with the bare polymer (only ∼3% in a large range), an increment of 95% for the oxygen barrier properties, and a very low water vapor transmission rate (WVTR) (∼96% reduction respect to PET substrate). This shows that graphene film may be an important alternative to conventional transparent electrode materials. We also speculate on the possibility to modulate polymer permeability at the nanoscale just applying a controlled-nanoporosity graphene layer.

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A method was developed for generating transparent and hydrophobic nanolayers chemisorbed onto flexible substrates of ethylene tetrafluoroethylene-silicon oxide (ETFE-SiOx). In particular, the effect of the deposition time and of the precursor molecule on the nanocoating process was analyzed with the aim of pursuing an optimization of the above method in an industrial application perspective. It was found that precursor molecule of triethoxysilane allowed to obtain better hydrophobic properties on the SiOx surface in shorter times compared to trichlorosilane, reaching the 92 % of final contact angle (CA) value of 106°after only 1 h of deposition. The optical properties and surface morphology were also assessed in function of time, revealing that an initial transparency reduction is followed by a subsequent transmittance increase during the self assembly of fluoroalkylsilanes on the SiOx surface, coherently with the surface roughness analysis data. Encouraging results were also obtained in terms of oleophobic properties improvement of the nanocoated surfaces.

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