Hostname: page-component-8448b6f56d-qsmjn Total loading time: 0 Render date: 2024-04-18T07:25:51.792Z Has data issue: false hasContentIssue false
  • English
  • Français

Isotropic/nematic and sol/gel transitions in aqueous suspensions of size selected nontronite NAu1

Published online by Cambridge University Press:  09 July 2018

L. J. Michot ,
E. Paineau ,
I. Bihannic ,
S. Maddi ,
J. F. L. Duval ,
C. Baravian ,
P. Davidson  and
P. Levitz
L. J. Michot*
Affiliation:
Laboratoire Interdisciplinaire des Environnements Continentaux, CNRS-Université de Lorraine UMR 7360, BP40, 54500 Vandoeuvre, France Physicochimie des Electrolytes, Colloïdes et Sciences Analytiques, CNRS-UPMC – ESPCI UMR 7195 - 4 place Jussieu, case courrier 51, 75005 Paris, France
E. Paineau
Affiliation:
Laboratoire Interdisciplinaire des Environnements Continentaux, CNRS-Université de Lorraine UMR 7360, BP40, 54500 Vandoeuvre, France Laboratoire de Physique des Solides, CNRS-Université Paris-Sud UMR 8502, Bât 510, 91405 Orsay Cedex, France
I. Bihannic
Affiliation:
Laboratoire Interdisciplinaire des Environnements Continentaux, CNRS-Université de Lorraine UMR 7360, BP40, 54500 Vandoeuvre, France
S. Maddi
Affiliation:
Laboratoire Interdisciplinaire des Environnements Continentaux, CNRS-Université de Lorraine UMR 7360, BP40, 54500 Vandoeuvre, France
J. F. L. Duval
Affiliation:
Laboratoire Interdisciplinaire des Environnements Continentaux, CNRS-Université de Lorraine UMR 7360, BP40, 54500 Vandoeuvre, France
C. Baravian
Affiliation:
Laboratoire d'Energétique et de Mécanique Théorique et Appliquée, CNRS-Université de Lorraine UMR 7563, 2, Avenue de la Forêt de Haye, BP160, 54504 Vandoeuvre Cedex, France
P. Davidson
Affiliation:
Laboratoire de Physique des Solides, CNRS-Université Paris-Sud UMR 8502, Bât 510, 91405 Orsay Cedex, France
P. Levitz
Affiliation:
Physicochimie des Electrolytes, Colloïdes et Sciences Analytiques, CNRS-UPMC – ESPCI UMR 7195 - 4 place Jussieu, case courrier 51, 75005 Paris, France
*
*E-mail: laurent.michot@upmc.fr
Get access Rights & Permissions [Opens in a new window]

Abstract

The phase behaviour of aqueous suspensions of NAu1 nontronite was studied on size-selected particles by combining osmotic pressure measurements, visual observations under polarized light, rheological experiments and Small Angle X-ray Scattering (SAXS). NAu1 suspensions display a liquid crystalline behaviour as they exhibit a Isotropic/Nematic (I/N) transition that occurs before the sol/gel transition for ionic strengths below 10–3 M/L. This I/N transition shifts towards lower volume fractions for increasing particle anisotropy and its position in the phase diagram agrees well with the theoretical predictions for platelets. SAXS measurements reveal the presence of characteristic interparticular distances in the isotropic, nematic and gel phases. In the gel phase a local lamellar order is observed which shows that the “house of cards” model is not appropriate for describing the gel structure in swelling clay materials at low ionic strength. Furthermore, by combining results from osmotic pressure measurements and X-ray scattering, it appears that the pressure of the system can be well described using a simple Poisson-Boltzmann treatment based on the repulsion between charged infinite parallel planes. In terms of rheological properties, even if the thermodynamical status of the sol/gel transition remains partially unclear, the yield stress and elasticity of the gels can be easily renormalized for all particle sizes on the basis of the volume of the particles. Furthermore, rheological modelling of the flow curves shows that for all the particles an approach based on excluded volume effects captures most features of nontronite suspensions.

Keywords

isotropic/nematic transitionsol/gel transitionrheologyelectrostaticsaqueous transitionsnontronite
Type
Research Article
Information
Clay Minerals , Volume 48 , Issue 5 , December 2013 , pp. 663 - 685
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2013

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

§

Deceased

References

Abend, S. & Lagaly, G. (2000) Sol-gel transitions of sodium montmorillonite dispersions. Applied Clay Science, 16, 201–227.CrossRefGoogle Scholar
Aboutalebi, S.H., Gudarzi, M.M., Zheng, Q.B. & Kim, J.K. (2011) Spontaneous formation of liquid crystals in ultralarge graphene oxide dispersions. Advanced Functional Materials, 21, 2978–2988.CrossRefGoogle Scholar
Adachi, Y., Nakaishi, K. & Tamaki, M. (1998) Viscosity of a dilute suspension of sodium montmorillonite in an electrostatically stable condition. Journal of Colloid and Interface Science, 198, 100–105.CrossRefGoogle Scholar
Baravian, C., Vantelon, D. & Thomas, F. (2003) Rheological determination of interaction potential energy for aqueous clay suspensions. Langmuir, 19, 8109–8114.CrossRefGoogle Scholar
Baravian, C., Michot, L.J., Paineau, E., Bihannic, I., Davidson, P., Imperor-Clerc, M., Belamie, E. & Levitz, P. (2010) An effective geometrical approach to the structure of colloidal suspensions of very anisometric particles. Europhysics Letters, 90, Article # 36005.CrossRefGoogle Scholar
Bates, M.A. & Frenkel, D. (1999) Nematic-isotropic transition in polydisperse systems of infinitely thin platelets. Journal of Chemical Physics, 110, 6553–6559.CrossRefGoogle Scholar
Bickmore, B.R., Bosbach, D., Hochella, M.F. Jr, Charlet, L. & Rufe, E. (2001) In situ atomic force microscopy of hectorite and nontronite dissolution: Implications for phyllosilicate edge surface structure and dissolution mechanisms. American Mineralogist, 86, 411–423.CrossRefGoogle Scholar
Bier, M., Harnau, L. & Dietrich, S. (2005) Free isotropicnematic interfaces in fluids of charged plate-like colloids. Journal of Chemical Physics, 123, article # 114906Google Scholar
Bihannic, I., Baravian, C., Duval, J.F.L., Paineau, E., Meneau, F., Levitz, P., de Silva, J., Davidson, P. & Michot, L.J. (2010) Orientational order of colloidal disk-shaped particles under shear-flow conditions: a rheological-Small-Angle X-ray Scattering study. Journal of Physical Chemistry B, 114, 16347–16355.CrossRefGoogle ScholarPubMed
Bonnet-Gonnet, C. (1993) Dégonflement et regonflement osmotiques de dispersions de latex. PhD Thesis, Université Paris VI, France.Google Scholar
Bradenburg, U. & Lagaly, G. (1988) Rheological properties of sodium montmorillonite dispersions. Applied Clay Science, 3, 263–279.Google Scholar
Broughton, G. & Squires, L. (1936) The gelation of bentonite suspensions. Journal of Physical Chemistry, 40, 1041–1053.CrossRefGoogle Scholar
Browne, A.B.D., Clarke, S.M. & Rennie, A.R. (1998) Ordered phase of plate-like particles in concentrated dispersions. Langmuir, 14, 3129–3132.Google Scholar
Cadène, A., Durand-Vidal, S., Turq, P. & Brendle, J. (2005) Study of individual Na-montmorillonite particles size, morphology, and apparent charge. Journal of Colloid and Interface Science, 285, 719–730.CrossRefGoogle ScholarPubMed
Callaghan, I.C. & Ottewill, R. (1974) Interparticle forces in montmorillonite gels. Faraday Discussions, Chemical Society, 57, 110–118.CrossRefGoogle Scholar
Dan, B., Behabtu, N., Martinez, A., Evans, J.S., Kosynkin, D.V., Tour, J.M., Pasquali, M. & Smalyukh, I.I. (2011) Liquid crystals of aqueous, giant graphene oxide flakes. Soft Matter, 7, 11154–11159.CrossRefGoogle Scholar
Davidson, P. & Gabriel, J-C.P. (2005) Mineral liquid crystals. Current Opinions in Colloid and Interface Science, 9, 377–383.Google Scholar
De Azevedo, E.N., Engelsberg, M., Fossum, J.O. & de Souza, R.E. (2007) Anisotropic water diffusion in nematic self-assemblies of clay nanoplatelets suspended in water. Langmuir, 23, 5100–5105.CrossRefGoogle ScholarPubMed
Donkai, N., Hoshino, H., Kajiwara, K. & Miyamoto, T. (1993) Lyotropic mesophase of imogolite. III: Observation of liquid crystal structure by scanning electron and novel polarized optical microscopy. Die Makromoleculare Chemie, 194, 559–580.Google Scholar
Durand-Vidal, S., Turq, P., Marang, L., Pagnoux, C. & Rosenholm, J.B. (2005) Determination of the effective charge of different nanocolloids at high ionic strength using conductivity and acoustophoresis. Colloids and Surfaces. A, Physicochemical and Engineering Aspects, 267, 117–121.Google Scholar
Fraden, S., Maret, G., Caspar, D.L.D. & Meyer, R.B. (1989) Isotropic-nematic phase transition and angular correlations in isotropic suspensions of tobacco mosaic virus. Physical Review Letters, 63, 2068–2071.CrossRefGoogle ScholarPubMed
Freundlich, H. (1928) On thixotropy. Kolloid Zeitschrift, 46, 289–307.CrossRefGoogle Scholar
Gabriel, J.C.P., Sanchez, C. & Davidson, P. (1996) Observation of nematic liquid–crystal textures in aqueous gels of smectite clays. Journal of Physical Chemistry B, 100, 11139–11143.Google Scholar
Gabriel, J.C.P., Camerel, F., Lemaire, B.J., Desvaux, H. Davidson, P. & Batail, P. (2001) Swollen liquidcrystalline lamellar phase based on extended solidlike sheets. Nature, 413, 504–508.CrossRefGoogle ScholarPubMed
Gates, W.P., Slade, P.G., Manceau, A. & Lanson, B. (2002) Site occupancies by iron in nontronites. Clays and Clay Minerals, 50, 223–239.CrossRefGoogle Scholar
Harnau, L. (2008) Structure and thermodynamics of platelet dispersions. Molecular Physics, 106, 1975–2000.CrossRefGoogle Scholar
Harvey, C.C. & Lagaly, G. (2006) Chapter 10.1 in: Handbook of Clay Science (Bergaya, F., Theng, B.G. & Lagaly, G., editors). Elsevier, Amsterdam.Google Scholar
Hauser, E.A. (1945) Colloidal chemistry of clays. Chemical Reviews, 40, 287–319.Google Scholar
Hauser, E.A. & Reed, C.E. (1937) Studies in thixotropy. II. The thixotropic behavior and structure of bentonite. Journal of Physical Chemistry, 41, 911–934.CrossRefGoogle Scholar
Hemmen, H., Ringdal, N.I., de Azevedo, E.N., Engelsberg, M., Hansen, E.L, Meheust, Y., Fossum, J.O. & Knudsen, K.D. (2009) The isotropic-nematic interface in suspensions of Na-fluorohectorite synthetic clay. Langmuir, 25, 12507–12515.CrossRefGoogle ScholarPubMed
Jönsson, B., Labbez, C. & Cabane, B. (2008) Interaction of nanometric clay platelets. Langmuir, 24, 11406–11413.CrossRefGoogle ScholarPubMed
Khandal, R.K. & Tadros, T.F. (1988) Application of viscoelastic measurements to the investigation of the swelling of sodium montmorillonite suspensions. Journal of Colloid and Interface Science, 125, 122–128.CrossRefGoogle Scholar
Kim, J.E., Han, T.H., Lee, S.H., Kim, J.Y., Ahn, C.W., Yun, J.M. & Kim, S.O. (2011) Graphene oxide liquid crystals. Angewandte Chemie–International Edition, 50, 3043–3047.Google ScholarPubMed
Lagaly, G. (1989) Principles of flow of kaolin and bentonite dispersions. Applied Clay Science, 4, 105–123.CrossRefGoogle Scholar
Langmuir, I. (1938) The role of attractive and repulsive forces on the formation of tactoids, thixotropic gels, protein crystals and coacervates. Journal of Chemical Physics, 6, 873–896.CrossRefGoogle Scholar
Lécolier, E. (1998) Suspension aqueuse de particules colloïdales anisotropes et chargées: structure et dynamique. PhD Thesis, Université d’Orléans, France.Google Scholar
Levitz, P., Lécolier, E., Mourchid, A., Delville, A. & Lyonnard, S. (2000) Liquid-solid transition of laponite suspensions at very low ionic strength: Long range electrostatic stabilisation of anisotropic colloids. Europhysics Letters, 45, 52–57.Google Scholar
Levitz, P., Zinsmeister, M., Davidson, P., Constantin, D. & Poncelet, O. (2008) Brownian dynamics over a rigid stran : heavily tailed relocation statistics in a simple geometry. Physical Review E, 78, 030102(R).CrossRefGoogle Scholar
Liu, S.Y, Zhang, J., Wang, N., Liu, W.R., Zhang, C.G. & Sun, D.J. (2003) Liquid-crystalline phases of colloidal dispersions of layered double hydroxides. Chemistry of Materials, 15, 3240–3241.CrossRefGoogle Scholar
Martin, C., Pignon, F., Magnin, A., Piau, J-M., Cabane, B. & Lindner, P. (2002) Dissociation of thixotropic clay gels. Physical Review E, 66, article no. 021401.CrossRefGoogle Scholar
Martin, C., Pignon, F., Magnin, A., Meireles, M., Lelièvre, V., Lindner, P. & Cabane, B. (2006) Osmotic compression and expansion of highly ordered clay dispersions. Langmuir, 22, 4065–4075.CrossRefGoogle ScholarPubMed
Meyer, S., Levitz, P. & Delville, A. (2001) Influence of the relative orientation of two charged anisotropic colloidal platelets on their electrostatic coupling: A (N,V,T) Monte Carlo study. Journal of Physical Chemistry B, 105, 10684–10690.Google Scholar
Miano, F. & Rabaioli, M.R. (1994) Rheological scaling of montmorillonite suspensions: the effect of electrolytes and polyelectrolytes. Colloids and Surfaces A, 84, 229–237.CrossRefGoogle Scholar
Michaels, A.S. & Bolger, J.C. (1962) The plastic flow behaviour of flocculated kaolin suspensions Industrial & Engineering Chemistry Fundamentals, 1, 153–162.CrossRefGoogle Scholar
Michot, L.J., Bihannic, I., Porsch, K., Maddi, S., Baravian, C., Mougel, J. & Levitz, P. (2004) Phase diagrams of Wyoming Na-montmorillonite clay. Influence of particle anisotropy. Langmuir, 20, 10829–10837.CrossRefGoogle ScholarPubMed
Michot, L.J., Bihannic, I., Pelletier, M. & Robert, J-L. (2005) Hydration and swelling of synthetic Nasaponites: Influence of layer charge. American Mineralogist, 90, 166–172.CrossRefGoogle Scholar
Michot, L.J., Bihannic, I., Maddi, S., Funari, S.S., Baravian, C., Levitz, P. & Davidson, P. (2006) Liquid-crystalline aqueous clay suspensions. Proceedings National Academy of Sciences of the USA, 103, 16101–16104.CrossRefGoogle ScholarPubMed
Michot, L.J., Bihannic, I., Maddi, S., Baravian, C., Levitz, P. & Davidson, P. (2008) Sol/gel and isotropic/nematic transitions in aqueous suspensions of natural nontronite clay. Influence of particle anisotropy. 1. Features of the I/N transition. Langmuir, 24, 3127–3139.CrossRefGoogle ScholarPubMed
Michot, L.J., Bihannic, I., Maddi, S., Baravian, C., Levitz, P. & Davidson, P. (2009) Sol/gel and isotropic/nematic transitions in aqueous suspensions of natural nontronite clay. Influence of particle anisotropy. 1. Gel structure and mechanical properties Langmuir, 25, 127–13.Google Scholar
Miyamoto, N. & Nakato, T. (2002) Liquid crystalline nature of K4Nb6O17 nanosheet sols and their macroscopic alignment. Advanced Materials, 14, 1267.3.0.CO;2-O>CrossRefGoogle Scholar
Miyamoto, N. & Nakato, T. (2004) Liquid crystalline nanosheet colloids with controlled particle size obtained by exfoliating single crystal of layered niobate K4Nb6O17 . Journal of Physical Chemistry B, 108, 6152–6159.CrossRefGoogle Scholar
Miyamoto, N., Iijima, I., Ohkubo, H. & Yamauchi, Y. (2010) Liquid crystal phases in the aqueous colloids of size-controlled fluorinated layered clay mineral nanosheets. Chemical Communications, 23, 4166–4168.Google Scholar
Mongondry, P., Tassin, J.F. & Nicolai, T. (2005) Revised state diagram of laponite dispersions Journal of Colloid and Interface Science, 283, 397–405.CrossRefGoogle ScholarPubMed
Mourad, M.C.D., Byelov, D.V., Petukhov, A.V., de Winter, D.A.M., Verkleij, A.J. & Lekkerkerker, H.N.W. (2009) Sol-gel transitions and liquid crystal phase transitions in concentrated aqueous suspensions of colloidal gibbsite platelets. Journal of Physical Chemistry B, 113, 11604–11613.CrossRefGoogle ScholarPubMed
Mourchid, A., Delville, A., Lambard, J., Lécolier, E. & Levitz, P. (1995) Phase diagram of colloidal dispersions of anisotropic charged particles: equilibrium properties, structure and rheology of laponite suspensions. Langmuir, 11, 1942–1950.CrossRefGoogle Scholar
Mourchid, A., Lécolier, E., Van Damme, H. & Levitz, P. (1998) On Viscoelastic, Birefringent, and Swelling Properties of Laponite Clay Suspensions: Revisited Phase Diagram. Langmuir, 14, 4718–4723.CrossRefGoogle Scholar
Norrish, K. (1954) The swelling of montmorillonite. Discussions, Faraday Society, 18, 120–133.CrossRefGoogle Scholar
Onsager, L. (1949) The effects of shape on the interaction of colloidal particles. Annals of New York Academy of Sciences, 51, 627–659.CrossRefGoogle Scholar
Paineau, E., Antonova, K., Baravian, C., Bihannnic, I., Davidson, P., Dozov, I., Impéror-Clerc, M., Levitz, P., Madsen, A., Meneau, F. & Michot, L.J. (2009) Liquidcrystalline nematic phase in aqueous suspensions of a disk-shaped natural beidellite clay. Journal of Physical Chemistry B, 113, 15858–15869.CrossRefGoogle ScholarPubMed
Paineau, E., Bihannic, I., Baravian, C., Philippe, A-M., Davidson, P., Levitz, P., Funari, S.S., Rochas, C. & Michot, L.J. (2011a) Aqueous suspensions of natural swelling clay minerals. 1. Structure and electrostatic interactions. Langmuir, 27, 5562–5573.Google ScholarPubMed
Paineau, E., Michot, L.J., Bihannic, I. & Baravian, C. (2011b) Aqueous suspensions of natural swelling clay minerals. 2 Rheological Characterization. Langmuir, 27, 7806–7819.Google ScholarPubMed
Philippe, A-M., Baravian, C., Imperor-Clerc, M., De Silva, J., Paineau, E., Bihannic, I., Davidson, P., Meneau, F., Levitz, P. & Michot, L.J. (2011) Rheo-SAXS investigation of shear-thinning behaviour of very anisometric repulsive disc-like clay suspensions. Journal of Physics: Condensed Matter, 23, article no. 194112.CrossRefGoogle Scholar
Philippe, A-M., Baravian, C., Bezuglyy, V., Angilella, J-R., Meneau, F., Bihannic, I. & Michot, L.J. (2013) Rheological study of two-dimensional very anisometric colloidal particle suspensions: From shearinduced orientation to viscous dissipation. Langmuir, 29, 5315–5324.CrossRefGoogle ScholarPubMed
Quemada, D. & Berli, C. (2002) Energy of interaction in colloids and. its implications in rheological modelling. Advances in Colloid and Interface Science, 98, 51–85.CrossRefGoogle Scholar
Ramsay, J.D.F. (1986) Colloidal properties of hectorite clay dispersions. Part 1. Rheology. Journal of Colloid and Interface Science, 109, 441–447.CrossRefGoogle Scholar
Ramsay, J.D.F. & Bunce, S.W. (1993) Swelling and dispersion of smectite clay colloids - Determination of structure by neutron-diffraction and Small-Angle-Neutron-Scattering. Journal of the Chemical Society, Faraday Transactions, 86, 3919–3926.Google Scholar
Ramsay, J.D.F. & Lindner, P. (1993) Small-angle neutron-scattering investigations of the structure of thixotropic dispersions of smectite clay colloids. Journal of the Chemical Society Faraday Transactions, 89, 4207–4214.CrossRefGoogle Scholar
Ramsay, J.D.F., Swanton, S.W. & Bunce, J. (1990) Swelling and dispersion of smectite clay colloids: Determination of structure by neutron diffraction and small-angle neutron scattering. Journal of the Chemical Society Faraday Transactions, 86, 3919–3926.CrossRefGoogle Scholar
Rand, B., Pekenc, E., Goodwin, J.W. & Smith, R.W. (1980) Investigation into the existence of edge-face coagulated structures in Na-montmorillonite suspensions. Journal of the Chemical Society, Faraday Transactions, 76, 225–235.Google Scholar
Ringdal, N.I., Fonseca, D.M., Hansen, E.L., Hemmen, H. & Fossum, J.O. (2010) Nematic textures in colloidal dispersions of Na-fluorohectorite synthetic clay. Physical Review E, 81, # 041702.CrossRefGoogle Scholar
Robertson, R.H.S. (1960) Mineral Use Guide. London, Cleaver Hume Press.Google Scholar
Russell, W.B., Saville, D.A. & Schowalter, W.R. (1991) Colloidal Dispersions. 2nd edition. Cambridge University Press, Cambridge, UK.Google Scholar
Saint-Michel, F., Pignon, F. & Magnin, A. (2003) Fractal behavior and scaling law of hydrophobic silica in polyol. Journal of Colloid and Interface Science, 267, 314–319.CrossRefGoogle ScholarPubMed
Tadros, T.F. (1996) Correlation of viscoelastic properties of stable and flocculated suspensions with their interparticle interactions. Advances in Colloid and Interface Science, 68, 97–200.CrossRefGoogle Scholar
Ten Brinke, A.J.W., Bailey, L., Lekkerkerker, H.N.W. & Maitland, G.C. (2007) Rheology modification in mixed shape colloidal dispersions. Part I: pure components. Soft Matter, 3, 1145–1162.CrossRefGoogle ScholarPubMed
Trappe, V, Prasad, V., Cipelletti, L., Segré, P.N. & Weitz, D.A. (2001) Jamming phase diagram for attractive particles. Nature, 411, 772–775.CrossRefGoogle ScholarPubMed
Trizac, E., Bocquet, L., Agra, R., Weiss, J-J. & Aubouy, M. (2002) Effective interactions and phase behaviour for a model clay suspension in an electrolyte. Journal of Physics: Condensed Matter, 14, 9339–9350.Google Scholar
Vali, H. & Bachmann, L. (1988) Ultrastructure and flow behavior of colloidal smectite dispersions. Journal of Colloid and Interface Science, 126, 278–291.CrossRefGoogle Scholar
Van der Beek, D. & Lekkerkerker, H.N.W. (2004) Liquid crystal phases of charged colloidal platelets. Langmuir, 20, 8582–8586.CrossRefGoogle ScholarPubMed
Van der Kooij, F.M. & Lekkerkerker, H.N.W. (1998) Formation of nematic liquid crystals in suspensions of hard colloidal platelets. Journal of Physical Chemistry B, 102, 7829–7832.CrossRefGoogle Scholar
Van der Kooij, F.M., Kassapidou, E. & Lekkerkerker, H.N.W. (2000) Liquid crystal phase transitions in suspensions of polydisperse plate-like particles. Nature, 406, 868–871.CrossRefGoogle Scholar
Van der Kooij, F.M., Van der Beek, D. & Lekkerkerker, H.N.W. (2001) Isotropic-nematic phase separation in suspensions of polydisperse colloidal platelets. Journal of Physical Chemistry B, 105, 1696–1700.CrossRefGoogle Scholar
Van Olphen, H. (1951) Rheological phenomena of clay soils in relation with the charge of the micelles. Discussions, Faraday Society, 11, 82–95.CrossRefGoogle Scholar
Van Olphen, H. (1964) Internal mutual flocculation in clay suspensions. Journal of Colloid and Interface Science, 19, 313–322.Google Scholar
Vroege, G.J. & Lekkerkerker, H.N.W. (1993) Theory of the isotropic nematic phase-separation for a solution of bidisperse rodlike particles. Journal of Physical Chemistry B, 97, 3601–3605.Google Scholar
Weber, C.H.M., Chiche, A., Krausch, G., Rosenfeldt, S., Ballauff, M., Harnau, L., Gottker-Schnetmann, I. & Mecking, S. (2007) Nano Letters, 7, 2024–2029.Google Scholar
Weiss, A. & Frank, R. (1961) Über den Bau der Gerü ste in thixotropen Gelen. Naturforschung, 16b, 141–142.Google Scholar
Xu, Z. & Gao, C. (2011a) Aqueous liquid crystals of graphene oxide. ACS Nano, 4, 2908–2915.Google Scholar
Xu, Z. & Gao, C. (2011b) Graphene chiral liquid crystals and macroscopic assembled fibres. Nature Communications, 2, article # 571.CrossRefGoogle Scholar