Bulk Graphene Production

The development of graphene fabrication protocols continues apace.  Now, we can dissolve it and then produce thin transparent films and liquid crystals.  The shear flexibility of what seems possible with graphene is astonishing.

We have already posted a lot on graphene and it is surely the most important materials discovery ever made.  Superlatives run out.

Multiple methods of fabrication are been explored of which this is one.

We are still some ways from commercial applications but still inside the next five years.

New Method for Producing Bulk Quantitites of Graphene

MAY 30, 2010

http://nextbigfuture.com/2010/05/new-method-for-producing-bulk.html

Researchers from Rice University and the Technion-Israel Institute of Technology unveiled a new method for producing bulk quantities of one-atom-thick sheets of carbon called graphene. 

* dissolve graphite in chlorosulphonic acid, a common industrial solvent.

* dissolve as much as two grams of graphene per liter of acid to produce solutions at least 10 times more concentrated than existing methods.

* Using the concentrated solutions of dissolved graphene, the scientists made transparent films that were electrically conductive and produced liquid crystals

* In liquid crystals, the individual sheets align themselves into domains, and having some measure of alignment allows you to flow the material through narrow openings to create fibers

Nature Nanotechnology - Spontaneous high-concentration dispersions and liquid crystals of graphene

Graphene combines unique electronic properties and surprising quantum effects with outstanding thermal and mechanical properties. Many potential applications, including electronics and nanocomposites, require that graphene be dispersed and processed in a fluid phase. Here, we show that graphite spontaneously exfoliates into single-layer graphene in chlorosulphonic acid, and dissolves at isotropic concentrations as high as ~2 mg ml^−1, which is an order of magnitude higher than previously reported values. This occurs without the need for covalent functionalization, surfactant stabilization, or sonication, which can compromise the properties of graphene6 or reduce flake size. We also report spontaneous formation of liquid-crystalline phases at high concentrations (~20–30 mg ml^−1). Transparent, conducting films are produced from these dispersions at 1,000Ω ^−1 and ~80% transparency. High-concentration solutions, both isotropic and liquid crystalline, could be particularly useful for making flexible electronics as well as multifunctional fibres.

Letter abstract

Nature Nanotechnology 

Published online: 30 May 2010 | doi:10.1038/nnano.2010.86

Spontaneous high-concentration dispersions and liquid crystals of graphene

Natnael Behabtu^1,3,7, Jay R. Lomeda^2,3,7, Micah J. Green^1,3,6, Amanda L. Higginbotham^2,3, Alexander Sinitskii^2,3, Dmitry V. Kosynkin^2,3, Dmitri Tsentalovich^1,3, A. Nicholas G. Parra-Vasquez^1,3, Judith Schmidt⁴, Ellina Kesselman⁴, Yachin Cohen⁴, Yeshayahu Talmon⁴, James M. Tour^2,3,5 & Matteo Pasquali^1,2,3

Abstract

Graphene combines unique electronic properties and surprising quantum effects with outstanding thermal and mechanical properties^1,2, 3, 4. Many potential applications, including electronics and nanocomposites, require that graphene be dispersed and processed in a fluid phase⁵. Here, we show that graphite spontaneously exfoliates into single-layer graphene in chlorosulphonic acid, and dissolves at isotropic concentrations as high as ~2 mg ml⁻¹, which is an order of magnitude higher than previously reported values. This occurs without the need for covalent functionalization, surfactant stabilization, or sonication, which can compromise the properties of graphene⁶ or reduce flake size. We also report spontaneous formation of liquid-crystalline phases at high concentrations (~20–30 mg ml⁻¹). Transparent, conducting films are produced from these dispersions at 1,000Ω □⁻¹ and ~80% transparency. High-concentration solutions, both isotropic and liquid crystalline, could be particularly useful for making flexible electronics as well as multifunctional fibres.

1. Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, USA
2. Richard E. Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, USA
3. Department of Chemistry, Rice University, Houston, Texas 77005, USA
4. Department of Chemical Engineering, Technion—Israel Institute of Technology, Haifa 32000, Israel
5. Department of Mechanical Engineering and Materials Science, Rice University, Houston, Texas 77005, USA
6. Present address: Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79409, USA
7. These authors contributed equally to this work

Correspondence to: James M. Tour^2,3,5 e-mail: tour@rice.edu

Correspondence to: Matteo Pasquali^1,2,3 e-mail: mp@rice.edu