(603a) Development of a Graphene Oxide Based Composite to Express Multifunctionality of Interest for Aviation Industries.

Graphene and its derivatives show unique characteristics like high electrical conductivity, low density and high surface area making them a reasonable option for various applications, i.e. de-icing, water impermeability and corrosion protection. [1,2]
However, a cost efficient and environmentally friendly industrial production of graphene-based materials is not established yet.

In the last decade, the scientific community put a lot of effort in producing graphene derivatives, whereby fabrication via the exfoliation of graphite are commonly used for large scale-production.[3]
This method leads to graphene oxide (GO) due to the simultaneous oxidation of the aromatic backbone during the process. Further reduction of the oxidic groups via different reducing agents or thermal decomposition produces reduced graphene oxide (rGO), which expresses a significant conductivity. [4]
This final product can be coated on surfaces to enhance their properties, as reported by Bondavalli et al. on the application of spray-coating of nanomaterials for electrical application. [5]

In our work, we aim to transfer the incredible nanoscale-properties of graphene to the scale of industrial applications by expressing multifunctional features.
First, we utilize electrochemical exfoliation on graphite to produce graphene oxide in a straightforward and up-scalable way.
The process involves a swelling with diluted NaOH, an exfoliation with diluted H₂SO₄ and a post-treatment step keeping the overall environmental impact low.
The reduction of graphene oxide is executed in an environmental-caring approach by using ascorbic acid over more harmful chemicals. [4]
Second, by applying the rGO-powder via spray-coating on different test panels, we investigate the conductivity of the layers.
Finally, we utilize these conductive materials to test De-Icing properties by means of Joule's heating, water uptake of the composite and lighting strike protection.

Specifically, by applying increasing amounts of rGO, the resistance of the layer is adjustable to suit de-icing applications.
For powder layers of thickness about 5 μm, we find sheet resistances down to about 150 Ω/sq. This corresponds to about 2 mg rGO per cm². Then, we apply a potential to the test panel to achieve electrical heating monitored by thermal imaging.
Reproducibility of the layer, multiple heating cycles and various conditions are investigated to fully characterise the functionality and show the reliability of the rGO-based heating layer. We employ SEM/EDX, AFM and Raman spectroscopy to additionally characterise the system. During the talk, we will present the results reported on our submitted paper on the up-scaling production of graphene oxide, and show how our composite can express multifunctionalities.

To conclude, the implementation of graphene oxide related species into next generation coating systems paves the way for novel green technological advances as weight-saving, i.e. reduction of fuel consumption in aeronautical vehicles. Moreover, via a multilayering strategy we intent to bring together the individual properties we have observed in graphene based materials, to develop next generation coatings for industrial applications.

Bibliography

(1) Raji, A.-R. O.; Varadhachary, T.; Nan, K.; Wang, T.; Lin, J.; Ji, Y.; Genorio, B.; Zhu, Y.; Kittrell, C.; Tour, J. M. ACS Applied Materials & Interfaces 2016, 8, PMID: 26780972, 3551–3556.(2) Chauhan, D. S.; Quraishi, M.; Ansari, K.; Saleh, T. A. Progress in Organic Coatings 2020, 147, 105741.
(3) Whitener, K. E.; Sheehan, P. E. Diamond and Related Materials 2014, 46, 25–34.
(4) De Silva, K.; Huang, H.-H.; Joshi, R.; Yoshimura, M. Carbon 2017, 119, 190–199.
(5) Bondavalli, P.; Pribat, D.; Legagneux, P.; Martin, M.-B.; Hamidouche, L.; Qassym, L.; Feugnet, G.; Trompeta, A.-F.; Charitidis, C. A. Journal of Physics: Materials 2019, 2, 032002