To date, aqueous stable graphene flakes solutions can be obtained by simple REDOX reactions. 1–5 Most of the current applications regarding graphene require ordered nanostructured composites materials. Liquid crystal phases ordering represent an opportunity to arrange them into macroscopic assemblies with long-range ordering. 1,2 Preparing organized materials and thin films from these dispersions then requires a good control of the liquid crystal ordering during the deposition and the drying of the films. As a matter of fact, it turns out that graphene flakes easily align at high shear.3,4 On the other hand, Graphene Flakes Liquid Crystals (GFLC) exhibit a very interesting behaviour at low shear or under small displacements, thin films often shows peculiar patterns (such as the periodic textures shown in Fig.72-72). We have shown how to create and stabilize large-sized periodic textures in GFLC. The patterns have been characterized under optical and electronic microscopies. Their stability can be explained by the competition between the anchoring field of the substrate and the presence of a yield stress resulting from the peculiar elastic and rheological properties of the GFLC. Our findings also clarify why longstanding hypotheses on the presence of exotic phases1 at large concentrations are present in the literature.
References [1] Zakri, C.; Blanc, C.; Grelet, E.; Zamora-Ledezma, C.; Puech, N.; Anglaret, E.; Poulin, P. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 2013, 371, 20120499..
[2] Zamora-Ledezma, C.; Puech, N.; Zakri, C.; Grelet, E.; Moulton, S. E.; Wallace, G. G.; Gambhir, S.; Blanc, C.; Anglaret, E.; Poulin, P. The journal of physical chemistry letters 2012, 3, 2425–2430..
[3] Poulin, P.; Jalili, R.; Neri, W.; Nallet, F.; Divoux, T.; Colin, A.; Aboutalebi, S. H.; Wallace, G.; Zakri, C. Proceedings of the National Academy of Sciences 2016, 113, 11088–11093..
[4] Zamora-Ledezma, C.; Jeridi, H.; Anglaret, E.; Blanc, C. Orientations and periodic textures in graphene liquid crystals. 27th International Liquid Crystal Conference (ILCC2018). 2018..
[5] Xu, Z.; Gao, C. Nature communications 2011, 2, 571.