The importance of repulsive potential barriers for the dispersion of graphene using surfactants

We have dispersed graphene in water, stabilized by a range of 12 ionic and non-ionic surfactants. In all cases, the degree of exfoliation, as characterized by flake length and thickness, was similar. The dispersed flakes were typically 750 nm long and, on average, four layers thick. However, the dispersed concentration varied from solvent to solvent. For the ionic surfactants, the concentration scaled with the square of the zeta potential of the surfactant-coated flakes. This suggests that the concentration is proportional to the magnitude of the electrostatic potential barrier, which stabilizes surfactant-coated flakes against aggregation. For the non-ionic surfactants, the dispersed graphene concentration scaled linearly with the magnitude of the steric potential barrier stabilizing the flakes. However, the data suggested that other contributions are also important.

[1]  A. Reina,et al.  Large area, few-layer graphene films on arbitrary substrates by chemical vapor deposition. , 2009, Nano letters.

[2]  J. Coleman,et al.  Quantitative Evaluation of Surfactant-stabilized Single-walled Carbon Nanotubes: Dispersion Quality and Its Correlation with Zeta Potential , 2008 .

[3]  Andre K. Geim,et al.  The rise of graphene. , 2007, Nature materials.

[4]  Andre K. Geim,et al.  Two-dimensional atomic crystals. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[5]  A. Bourlinos,et al.  Liquid-phase exfoliation of graphite towards solubilized graphenes. , 2009, Small.

[6]  Mustafa Lotya,et al.  Measurement of multicomponent solubility parameters for graphene facilitates solvent discovery. , 2010, Langmuir : the ACS journal of surfaces and colloids.

[7]  SUPARNA DUTTASINHA,et al.  Graphene: Status and Prospects , 2009, Science.

[8]  J. Coleman,et al.  High-concentration solvent exfoliation of graphene. , 2010, Small.

[9]  J. Coleman,et al.  Liquid phase production of graphene by exfoliation of graphite in surfactant/water solutions , 2008, 0809.2690.

[10]  J. Coleman,et al.  High-yield production of graphene by liquid-phase exfoliation of graphite. , 2008, Nature nanotechnology.

[11]  J. Coleman,et al.  Flexible, transparent, conducting films of randomly stacked graphene from surfactant-stabilized, oxide-free graphene dispersions. , 2010, Small.

[12]  K. Novoselov,et al.  Graphene-based liquid crystal device. , 2008, Nano letters (Print).

[13]  J. Tour,et al.  High-yield organic dispersions of unfunctionalized graphene. , 2009, Nano letters.

[14]  J. Israelachvili.  Intermolecular and surface forces , 1985 .

[15]  大島 広行,et al.  Theory of colloid and interfacial electric phenomena , 2006 .

[16]  Irving P. Herman,et al.  Zeta-Potential Measurements of Surfactant-Wrapped Individual Single-Walled Carbon Nanotubes , 2007 .

[17]  A. Green,et al.  Solution phase production of graphene with controlled thickness via density differentiation. , 2009, Nano letters.

[18]  Etienne Goovaerts,et al.  Efficient Isolation and Solubilization of Pristine Single‐Walled Nanotubes in Bile Salt Micelles , 2004 .

[19]  Hiroyuki Ohshima,et al.  Theory of Colloid and Interfacial Electric Phenomena , 2006 .

[20]  H. Stone,et al.  Electrophoresis of a thin charged disk , 1995 .

[21]  J. Coleman,et al.  High-concentration, surfactant-stabilized graphene dispersions. , 2010, ACS nano.

[22]  R. J. Hunter,et al.  Introduction To Modern Colloid Science , 1993 .