Aspect ratio and polydispersity dependence of isotropic-nematic transition in discotic suspensions.

We demonstrate the strong dependency of the isotropic-nematic (I-N) transition of discotic suspensions on the aspect ratio (ξ = thickness/diameter) via control of the sizes of pristine ZrP crystals and subsequent exfoliation to monolayers. The size fractionation of the I-N transition facilitates the analysis of the effect of polydispersity. A systematic variation in the aspect ratio in the low aspect ratio region (0.001 < ξ < 0.01) showed that the I-N transition volume fraction increases with the aspect ratio in agreement with computer simulations. It was found that the transition volume fractions scale with aspect ratio φ_{I,N} = mξ^{1.36±0.07}, where the prefactor m strongly depends on size polydispersity for φ_{N} but does not depend on size polydispersity for φ_{I} with φ_{I} and φ_{N} being the volume fractions of the isotropic and the nematic phases on the cloud curves, respectively.

[1]  N. Miyamoto,et al.  Liquid Crystalline Nature of K4Nb6O17 Nanosheet Sols and Their Macroscopic Alignment , 2002 .

[2]  P. Reynolds,et al.  Phase behavior of mixtures of colloidal platelets and nonadsorbing polymers , 2002 .

[3]  P. Levitz,et al.  Magnetic colloidal particles as probes for the determination of the structure of Laponite suspensions , 2002 .

[4]  J. Gabriel,et al.  Observation of Nematic Liquid-Crystal Textures in Aqueous Gels of Smectite Clays , 1996 .

[5]  M. Dennison,et al.  Theory and computer simulation for the cubatic phase of cut spheres. , 2009, Physical review. E, Statistical, nonlinear, and soft matter physics.

[6]  B. Martínez-Haya,et al.  Characterization and Langmuir film properties of asphaltenes extracted from Arabian light crude oil , 2007 .

[7]  D M Fonseca,et al.  Nematic textures in colloidal dispersions of Na-fluorohectorite synthetic clay. , 2010, Physical review. E, Statistical, nonlinear, and soft matter physics.

[8]  P. Panine,et al.  The measurement by SAXS of the nematic order parameter of laponite gels , 2002 .

[9]  N. Kotov,et al.  Ultrathin graphite oxide–polyelectrolyte composites prepared by self‐assembly: Transition between conductive and non‐conductive states , 1996 .

[10]  A. Martí,et al.  Direct Ion Exchange of Tris(2,2‘-bipyridine)ruthenium(II) into an α-Zirconium Phosphate Framework , 2003 .

[11]  H. Lekkerkerker,et al.  Isotropic-Nematic Phase Separation in Suspensions of Polydisperse Colloidal Platelets , 2001 .

[12]  A. Clearfield,et al.  Crystallography and structure of .alpha.-zirconium bis(monohydrogen orthophosphate) monohydrate , 1969 .

[13]  A. Cuetos,et al.  Simulation study of discotic molecules in the vicinity of the isotropic–liquid crystal transition , 2009 .

[14]  On the isotropic-liquid crystal phase separation in a solution of rodlike particles of different lengths , 1984 .

[15]  K. Domen,et al.  Preparation of Porous Niobium Oxides by Soft-Chemical Process and Their Photocatalytic Activity , 1997 .

[16]  H. Lekkerkerker,et al.  Liquid crystal phase transitions in suspensions of polydisperse plate-like particles , 2000, Nature.

[17]  D. Frenkel,et al.  Nematic–isotropic transition in polydisperse systems of infinitely thin hard platelets , 1999 .

[18]  A. Chamoux,et al.  A theoretical study of the isotropic cut sphere fluids , 1998 .

[19]  A J Koster,et al.  Nucleosomes, linker DNA, and linker histone form a unique structural motif that directs the higher-order folding and compaction of chromatin. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[20]  A. Galindo,et al.  Surface ordering and capillary phenomena of confined hard cut-sphere particles. , 2007, Soft matter.

[21]  D. Frenkel,et al.  Phase behavior of disklike hard-core mesogens. , 1992, Physical review. A, Atomic, molecular, and optical physics.

[22]  Irving Langmuir,et al.  The Role of Attractive and Repulsive Forces in the Formation of Tactoids, Thixotropic Gels, Protein Crystals and Coacervates , 1938 .

[23]  Michael Treacy,et al.  Electron Microscopy Study of Delamination in Dispersions of the Perovskite-Related Layered Phases K[Ca2Nan−3NbnO3n+1]: Evidence for Single-Layer Formation , 1990 .

[24]  K. Domen,et al.  Preparation of Ion-Exchangeable Thin Films of Layered Niobate K4Nb6O17 , 1998 .

[25]  S. Clarke,et al.  Ordered Phase of Platelike Particles in Concentrated Dispersions , 1998 .

[26]  H. Lekkerkerker,et al.  Nematic ordering vs. gelation in suspensions of charged platelets , 2003 .

[27]  D. Frenkel,et al.  Influence of polydispersity on the phase behavior of colloidal liquid crystals: A Monte Carlo simulation study , 1998 .

[28]  M. A. Bates.  Influence of particle shape on the nematic—isotropic transition of colloidal platelet systems , 1999 .

[29]  Aryadi Suwono,et al.  Measurement of property relationships of nano-structure micelles and coacervates of asphaltene in a pure solvent , 2001 .

[30]  Thomas E. Mallouk,et al.  Layer-by-Layer Assembly of Intercalation Compounds and Heterostructures on Surfaces: Toward Molecular "Beaker" Epitaxy , 1994 .

[31]  T. Odijk.  Theory of lyotropic polymer liquid crystals , 1986 .

[32]  Hyuk-Nyun Kim,et al.  Nanoscale Tubules Formed by Exfoliation of Potassium Hexaniobate , 2000 .

[33]  N. Miyamoto,et al.  Liquid crystalline nanosheet colloids with controlled particle size obtained by exfoliating single crystal of layered niobate k(4)nb(6)o(17). , 2004, The journal of physical chemistry. B.

[34]  Daan Frenkel,et al.  Monte Carlo study of the isotropic-nematic transition in a fluid of thin hard disk , 1982 .

[35]  A. Cuetos,et al.  Columnar phases of discotic spherocylinders. , 2008, The Journal of chemical physics.

[36]  S. Marčelja,et al.  Onsager transition in hard plate fluid , 1977 .

[37]  Mamoru Watanabe,et al.  Macromolecule-like Aspects for a Colloidal Suspension of an Exfoliated Titanate. Pairwise Association of Nanosheets and Dynamic Reassembling Process Initiated from It , 1996 .

[38]  Ladislav Kavan,et al.  Graphene nanoplatelet cathode for Co(III)/(II) mediated dye-sensitized solar cells. , 2011, ACS nano.

[39]  G. Alberti,et al.  Inorganic ion-exchange pellicles obtained by delamination of α-zirconium phosphate crystals , 1985 .

[40]  L. Onsager.  THE EFFECTS OF SHAPE ON THE INTERACTION OF COLLOIDAL PARTICLES , 1949 .

[41]  D. Frenkel,et al.  Do cylinders exhibit a cubatic phase , 1999, cond-mat/9903324.

[42]  J. B. Chatterjea,et al.  Studies on platelets. IX. Observations on the properties and mechanism of action of a potent platelet agglutinin detected in the serum of a patient with idiopathic thrombocytopenic purpura, with a note on the pathogenesis of the disease. , 1953, Blood.

[43]  Rui P. S. Fartaria,et al.  Density minimum in the isotropic–nematic transition of hard cut-spheres , 2009 .

[44]  Freezing of polydisperse hard spheres , 1999 .

[45]  M. Pileni,et al.  Size Distribution of Cobalt Nanocrystals: A Key Parameter in Formation of Columns and Labyrinths in Mesoscopic Structures , 2005, Advances in Materials.

[46]  D. Sun,et al.  Stable smectic phase in suspensions of polydisperse colloidal platelets with identical thickness. , 2009, Physical review. E, Statistical, nonlinear, and soft matter physics.

[47]  H. Lekkerkerker,et al.  Liquid crystal phases of charged colloidal platelets. , 2004, Langmuir : the ACS journal of surfaces and colloids.

[48]  M. Rodríguez-Pérez,et al.  Functionalized graphene sheet filled silicone foam nanocomposites , 2008 .

[49]  George Jackson,et al.  A RE-EXAMINATION OF THE PHASE DIAGRAM OF HARD SPHEROCYLINDERS , 1996 .

[50]  Hyuk-Nyun Kim,et al.  Characterization of Zirconium Phosphate/Polycation Thin Films Grown by Sequential Adsorption Reactions , 1997 .

[51]  P. Levitz,et al.  Phase diagram of colloidal dispersions of anisotropic charged particles : equilibrium properties, structure, and rheology of laponite suspensions , 1995 .

[52]  Peter V. Coveney,et al.  Simulating the rheology of dense colloidal suspensions using dissipative particle dynamics , 1997 .

[53]  H. Lekkerkerker,et al.  Isotropic-nematic interface and wetting in suspensions of colloidal platelets. , 2006, Physical review letters.

[54]  F. Osterloh.  Solution self-assembly of magnetic light modulators from exfoliated perovskite and magnetite nanoparticles. , 2002, Journal of the American Chemical Society.

[55]  Y. Tanabe,et al.  Carbon Alloys—Multi-functionalization , 2008 .

[56]  J. Susini,et al.  First Direct Visualization of Oriented Mesostructures in Clay Gels by Synchrotron-Based X-ray Fluorescence Microscopy , 2001 .

[57]  A. Cuetos,et al.  Phase behavior of hard colloidal platelets using free energy calculations. , 2011, The Journal of chemical physics.

[58]  H. Lekkerkerker,et al.  Formation of Nematic Liquid Crystals in Suspensions of Hard Colloidal Platelets , 1998 .

[59]  A. Clearfield,et al.  Preparation of α-zirconium phosphate nanoplatelets with wide variations in aspect ratios , 2007 .

[60]  T. Mallouk,et al.  Photoinduced Energy and Electron Transfer Reactions in Lamellar Polyanion/Polycation Thin Films: Toward an Inorganic “Leaf” , 1999 .

[61]  L. Robeson,et al.  Polymer nanotechnology: Nanocomposites , 2008 .

[62]  G J Vroege,et al.  Phase transitions in lyotropic colloidal and polymer liquid crystals , 1992 .

[63]  Liberato Manna,et al.  Semiconductor Nanorod Liquid Crystals , 2002 .

[64]  Dejun Sun,et al.  Liquid-Crystalline Phases of Colloidal Dispersions of Layered Double Hydroxides , 2003 .

[65]  S. Lago,et al.  Parsons–Lee approach for oblate hard spherocylinders , 2010 .

[66]  T. Mallouk,et al.  Prying Apart Ruddlesden−Popper Phases: Exfoliation into Sheets and Nanotubes for Assembly of Perovskite Thin Films , 2000 .

[67]  K. Subbarao,et al.  Germination of Sclerotinia minor and S. sclerotiorum Sclerotia Under Various Soil Moisture and Temperature Combinations. , 2003, Phytopathology.

[68]  A. Cuetos,et al.  Columnar phases of discotics with orientation-dependent interactions. , 2009, The Journal of chemical physics.

[69]  A. Rennie,et al.  Dispersions of plate-like colloidal particles--cubatic order? , 2010, Journal of colloid and interface science.

[70]  J. Gabriel,et al.  Mineral liquid crystals , 2005 .

[71]  H. H. Wensink,et al.  Phase diagram of hard colloidal platelets: a theoretical account , 2009, 0908.1362.

[72]  S. Kelly,et al.  Electronic Charge Transport in Extended Nematic Liquid Crystals , 2006 .

[73]  M. Okazaki,et al.  Polymerizable discoticnematic triphenylene derivatives and their application to an optically anisotropic film , 2000 .

[74]  A. Clearfield,et al.  Mechanism of ion exchange in zirconium phosphates. 20. Refinement of the crystal structure of .alpha.-zirconium phosphate , 1977 .

[75]  H. H. Wensink,et al.  Isotropic-Nematic Density Inversion in a Binary Mixture of Thin and Thick Hard Platelets , 2001 .

[76]  Bruno J. Lemaire,et al.  Swollen liquid-crystalline lamellar phase based on extended solid-like sheets , 2001, Nature.

[77]  B. Dubertret,et al.  Colloidal nanoplatelets with two-dimensional electronic structure. , 2011, Nature materials.

[78]  H. Lekkerkerker,et al.  Gravity-induced liquid crystal phase transitions of colloidal platelets. , 2004, The Journal of chemical physics.

[79]  Yves Méheust,et al.  The isotropic-nematic interface in suspensions of Na-fluorohectorite synthetic clay. , 2009, Langmuir : the ACS journal of surfaces and colloids.

[80]  Frenkel,et al.  Phase diagram of a system of hard spherocylinders by computer simulation. , 1990, Physical review. A, Atomic, molecular, and optical physics.