Binary Clay – Graphene Oxide Liquid Crystals*

Colloidal suspensions (CS) of electrically charged nanosheets (NSTs) form liquid crystalline phases in polar solvents, such as graphene oxide¹ or clays^2,3. Self organization of NSTs due to competing van der Waals attraction and electrostatic repulsion forces can form several coexisting phases such as isotropic (I), nematic (N) or lamellar (L). Several single-component CS^1,2 exhibit transition from I to N liquid crystalline phase; moreover, existence of L phase for CS of electrically charged NSTs has been observed recently⁴.
In contrary, complexity of binary CS (BCS) of charged NSTs can result in multi-phase systems. This study is focused on BCS of negatively charged synthetic clay⁵ and graphene oxide, serving as promising precursor for fabrication of clay-graphene oxide mixed ionic-electronic conductors. Results obtained using X-ray diffraction (SAXS, WAXS) and imaging (optical, MRI) techniques will be discussed, emphasizing formation of N and mixed-domain states.
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3.Hemmen, H. et al. Langmuir 25, 12507–12515 (2009).
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