**4. Conclusions**

In summary, it has been demonstrated that electrospun nanocomposite coatings of PVC improve the corrosion resistance of the aluminum alloy 6061T6 due to the high hydrophobic character (even superhydrophobic) of the resulting surfaces, which may be explained by the roughness and fibrous topography of these coatings, which seems to produce a water-coating contact corresponding to the Cassie-Baxter state.

Nanocomposite films of PVC containing ZnO nanoparticles were successfully prepared using one-step electrospinning technique and the corrosion electrochemical tests revealed that heating the nanocomposite PVC-ZnO structures 20◦ higher than *Tg* of the polymer allows obtaining an excellent and better anti-corrosion behaviour. This may be explained by a better distribution of the ZnO nanoparticles due to the movement of the polymer chains above *Tg*, which compensates for the decrease in the hydrophobic behaviour of the fibers at such high temperatures. Finally, Tafel polarization tests have shown that the corrosion current density could be reduced in two orders of magnitude with the use of these electrospun coatings and pitting corrosion tests also demonstrated that the nanocomposite surfaces enhance the resistance of aluminum against localized corrosion.

Finally, it is worth to notice that real life conditions can be far different from those of static laboratory tests. In particular water condensation or the impact of water drops can lead to a Wenzel-like state that can limit the employment of these coatings in automotive or aeronautical applications. The dynamic test should be necessary to guarantee the good behavior of these coatings in real life applications.

**Author Contributions:** Conceptualization, A.I. and P.J.R.; Methodology, A.I. and P.J.R.; Validation, A.I., P.J.R., and R.R.; Formal Analysis, A.I., P.J.R., C.B and J.F.P.; Investigation, A.I., P.J.R., S.L., A.M., J.F.P. and R.R.; Writing—Original Draft Preparation, P.J.R. and A.I.; Writing—Review and Editing, A.I., P.J.R. and R.R.; Supervision, P.J.R., C.B. and R.R.

**Funding:** This research was funded by the Spanish Economy and Competitiveness Ministry, FEDER (Project TRA2013-48603-C4-1-R-HELADA) and by the Public University of Navarra collaboration research gran<sup>t</sup> PRO-UPNA 18 (6107).

**Acknowledgments:** The authors would like to express their gratitude to Nadetech Inc. for the tune-up of the robot used for the deposition of the nanocoatings. Finally the authors would like to express their grateful acknowledgement for the support received from the Asociación de la Industria Navarra (AIN).

**Conflicts of Interest:** The authors declare no conflict of interest.
