Liquid Crystal Phases of Charged Colloidal Platelets

Beek, D. van der; Lekkerkerker, H. N. W.

doi:10.1021/la049455i

Cited by 123 publications

(143 citation statements)

References 38 publications

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“…This phenomenon can be explained by a simple osmotic compression model. 21,22 Using equations of state obtained from literature and from Monte Carlo computer simulations that we performed, we find good agreement with the experimentally determined individual phase heights.…”

Section: Introductionsupporting

confidence: 77%

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Gravity-induced liquid crystal phase transitions of colloidal platelets

Beek

Schilling

Lekkerkerker

2004

The Journal of Chemical Physics

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The influence of gravity on a suspension of sterically stabilized colloidal gibbsite platelets is studied. An initially isotropic-nematic biphasic sample of such a suspension develops a columnar phase on the bottom on prolonged standing. This phenomenon is described using a simple osmotic compression model. We performed Monte Carlo simulations of cut spheres with aspect ratio L/D ϭ1/15 and took data from the literature to supply the equations of state required for the model. We find that the model describes the observed three-phase equilibrium quite well.

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Section: Introductionsupporting

confidence: 77%

“…When sedimentation-diffusion equilibrium is reached, Eq. ͑1͒ describes the complete system: 21,22 Ϫ ͩ ‫ץ‬⌸ ‫ץ‬n ͪ ‫ץ‬n ‫ץ‬z ϭm*gn. ͑1͒…”

Section: Model a Sedimentation-diffusion Equilibriummentioning

confidence: 99%

Gravity-induced liquid crystal phase transitions of colloidal platelets

Beek

Schilling

Lekkerkerker

2004

The Journal of Chemical Physics

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“…From computer simulations by Veerman and Frenkel [37], and later Zhang et al [38], it was found that hard platelets may also form another liquid-crystal phase, namely the orientationally and 2D translationally ordered columnar (C) phase. This phase has also been observed experimentally in suspensions of sterically stabilised and charged colloidal plates [39][40][41]. There is a very interesting issue, raised in one of these reports [39], which is related to the inherent size polydispersity in these synthetic suspensions: it is quite surprising that such systems, with a rather high polydispersity of up to 25%, show the columnar liquid-crystal phase.…”

Section: Introductionmentioning

confidence: 68%

Evidence of the hexagonal columnar liquid-crystal phase of hard colloidal platelets by high-resolution SAXS

et al. 2005

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Abstract. We report Small-Angle X-ray Scattering (SAXS) measurements of the columnar phase of hard colloidal gibbsite platelets. We have been able to create large oriented domains of the columnar phase both perpendicular and parallel to the sample wall, varying the volume fraction of platelets and adding non-adsorbing polymer to the dispersion. In conjunction with the increased resolution of the SAXS setup, this allowed a detailed analysis of the columnar phase, providing unambiguous evidence for the hexagonal nature of the phase.

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“…In a polydisperse GO dispersion, large GO sheets generate excluded volume for small sheets giving rise to entropic rearrangement to form long range ordering resembling a liquid crystalline state. The critical theoretical volume fraction (Φ) for the transition between isotropic to nematic phase can be calculated based on Equation 1 which served as a model system for liquid crystal phases of charged colloidal platelets, [21,22] …”

Section: Birefringence Rheological Behavior and Spinnability Of Go Dmentioning

confidence: 99%

Scalable One‐Step Wet‐Spinning of Graphene Fibers and Yarns from Liquid Crystalline Dispersions of Graphene Oxide: Towards Multifunctional Textiles

Jalili

Aboutalebi

Esrafilzadeh

et al. 2013

Adv Funct Materials

376

426

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. (2013). Scalable one-step wet-spinning of graphene fibers and yarns from liquid crystalline dispersions of graphene oxide: towards multifunctional textiles. Advanced Functional Materials, 23 (43), 5345-5354.Scalable one-step wet-spinning of graphene fibers and yarns from liquid crystalline dispersions of graphene oxide: towards multifunctional textiles AbstractKey points in the formation of liquid crystalline (LC) dispersions of graphene oxide (GO) and their processability via wet-spinning to produce long lengths of micrometer-dimensional fibers and yarns are addressed. Based on rheological and polarized optical microscopy investigations, a rational relation between GO sheet size and polydispersity, concentration, liquid crystallinity, and spinnability is proposed, leading to an understanding of lyotropic LC behavior and fiber spinnability. The knowledge gained from the straightforward formulation of LC GO "inks" in a range of processable concentrations enables the spinning of continuous conducting, strong, and robust fibers at concentrations as low as 0.075 wt%, eliminating the need for relatively concentrated spinning dope dispersions. The dilute LC GO dispersion is proven to be suitable for fiber spinning using a number of coagulation strategies, including non-solvent precipitation, dispersion destabilization, ionic cross-linking, and polyelectrolyte complexation. One-step continuous spinning of graphene fibers and yarns is introduced for the first time by in situ spinning of LC GO in basic coagulation baths (i.e., NaOH or KOH), eliminating the need for post-treatment processes. The thermal conductivity of these graphene fibers is found to be much higher than polycrystalline graphite and other types of 3D carbon based materials. New insights are provided into the processing of liquid crystalline graphene oxide (GO) dispersion (containing large GO sheets) demonstrating a facile and scalable production of GO and reduced GO fibers and yarns with exciting properties such as high thermal conductivity. These results provide a universal platform for the development of solution-based processing methods, properties, and applications of liquid crystalline GO-based architectures. AbstractIn the present work, we address key points in the formation of liquid crystalline (LC) dispersions of graphene oxide (GO) and their processability via wet-spinning to produce long lengths of micron dimensional fibers and yarns. Based on rheological and polarized optical microscopy investigations, a rational relation between GO sheet size and polydispersity, concentration, liquid crystallinity and spinnability is proposed leading to the understanding of 2 lyotropic LC behavior and fiber spinnability. The knowledge gained from our straightforward formulation of LC GO "inks" in a range of processable concentrations enabled us to spin continuous conducting, strong and robust fibres at concentrations as low as 0.075 wt. % eliminating the need for relatively concentrated spinning dope dispersions. This concentration is the lowest ever rep...

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Liquid Crystal Phases of Charged Colloidal Platelets

Cited by 123 publications

References 38 publications

Gravity-induced liquid crystal phase transitions of colloidal platelets

Gravity-induced liquid crystal phase transitions of colloidal platelets

Evidence of the hexagonal columnar liquid-crystal phase of hard colloidal platelets by high-resolution SAXS

Scalable One‐Step Wet‐Spinning of Graphene Fibers and Yarns from Liquid Crystalline Dispersions of Graphene Oxide: Towards Multifunctional Textiles

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