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Ionic solutions of two-dimensional materials


Strategies for forming liquid dispersions of nanomaterials typically focus on retarding reaggregation, for example via surface modification, as opposed to promoting the thermodynamically driven dissolution common for molecule-sized species. Here we demonstrate the true dissolution of a wide range of important 2D nanomaterials by forming layered material salts that spontaneously dissolve in polar solvents yielding ionic solutions. The benign dissolution advantageously maintains the morphology of the starting material, is stable against reaggregation and can achieve solutions containing exclusively individualized monolayers. Importantly, the charge on the anionic nanosheet solutes is reversible, enables targeted deposition over large areas via electroplating and can initiate novel self-assembly upon drying. Our findings thus reveal a unique solution-like behaviour for 2D materials that enables their scalable production and controlled manipulation.

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Figure 1: Structure, dissolution and deposition of layered material salts.
Figure 2: The morphology of dissolved nanosheets.
Figure 3: Structure and self-assembly of dissolved nanosheets.
Figure 4: Electroplating a nanosheet solution.


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This publication was funded, in part, by the Engineering & Physical Sciences Research Council (EPSRC). L.P. & O.D.P. thank the Royal Academy of Engineering for funding the development of the HS-AFM and the NSQI Low Noise Lab for hosting the HS-AFM. We thank Martial Duchamp for his valuable assistance with the ‘PICO’ TEM at the Ernst–Ruska Research Centre. The authors are grateful to Milo Shaffer & Paul McMillan for helpful and supportive discussions.

Author information




C.A.H. and P.L.C. conceived the project. P.L.C., V.T., M.K.B.S., K.M.C. and C.A.H. made the intercalated compounds and solutions. M.K.B.S., K.M.C., P.L.C. & C.A.H. carried out X-ray analysis. L.P., O.D.P., P.L.C., K.M.C. and C.A.H. performed and analysed the AFM measurements. L.P. wrote the automated HS-AFM platelet detection and step height measurement algorithms. V.T. performed S/TEM and contributed to the analysis of the results. C.A.H. carried out the electroplating and Raman experiment. C.A.H. directed the study and wrote the paper. All authors discussed and developed the science and commented on the manuscript.

Corresponding author

Correspondence to Christopher A. Howard.

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The authors declare no competing financial interests.

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Cullen, P., Cox, K., Bin Subhan, M. et al. Ionic solutions of two-dimensional materials. Nature Chem 9, 244–249 (2017).

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