Gelation versus liquid crystal phase transitions in suspensions of plate-like particles

Mourad, Maurice C. D.; Wijnhoven, Judith E. G. J.; Zand, Daniëlle D. van ’t; Beek, D. van der; Lekkerkerker, H. N. W.

doi:10.1098/rsta.2006.1856

Cited by 35 publications

(44 citation statements)

References 27 publications

(40 reference statements)

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“…The spontaneous organization of nonspherical colloids has attracted great recent interest due to the wide range of potential applications of the resulting assemblies in photonic crystals [1][2][3][4], metamaterials [5], surface-enhanced Raman scattering sensors [6], and reinforced nanocomposites [7][8][9], as well as fundamental studies of liquid crystal phase transitions [10][11][12][13] and particle packing [14][15][16]. Among a large variety of nonspherical colloids, platelet particles are particularly interesting as they enable the bottom-up assembly of layered nanocomposites that mimic the nacreous layer of mollusk shells [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Bioinspired assembly of surface-roughened nanoplatelets

Lin

Huang

Jun

et al. 2010

Journal of Colloid and Interface Science

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Section: Introductionmentioning

confidence: 99%

Bioinspired assembly of surface-roughened nanoplatelets

Lin

Huang

Jun

et al. 2010

Journal of Colloid and Interface Science

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“…Nevertheless, gibbsite has the same generic rheological phase diagram (see figure 1) as discussed above for natural and synthetic clays. An important quantitative difference is that whereas for clays the tip of the sol nose is situated at a clay concentration of 1-2 wt% and a salt concentration of 10 −3 -10 −4 M [12,[16][17][18][19], for gibbsite it is located at a concentration of 40-50 wt% and a salt concentration of 5 × 10 −2 M [21,22]. Here we focus on the sol-gel transition at low salt strength (see figure 1), where repulsion is dominant.…”

Section: Introductionmentioning

confidence: 99%

Structure of the repulsive gel/glass in suspensions of charged colloidal platelets

Mourad

Byelov

Petukhov

et al. 2008

J. Phys.: Condens. Matter

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Rheological, optical and structural properties of colloidal suspensions of charge-stabilized gibbsite platelets across the sol-gel transition region are investigated. In this work we focus on samples with a low salt content (10 −4 M). While at a gibbsite concentration of 300 g l −1 , a nematic-columnar phase separation is observed, an arrested state with a nematic signature and highly elastic response has been observed for a concentration of 400 g l −1 . A temporal evolution of the structure of the arrested state, which leads to stronger interparticle correlations, has been observed on a timescale of 20 months. The results suggest that the arrested state develops into a glass with a columnar nematic structure.

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“…10,11 While particles of extreme anisotropy may show a rich liquid-crystalline phase diagram, 12 in general one observes a gel phase that arrests crystallisation. 13 In the semi-dilute regime they form a stiff repulsive gel. Shear induces alignment of the particles, thereby reducing overlaps and apparent viscosity.…”

Section: Introductionmentioning

confidence: 99%

Rheology modification in mixed shape colloidal dispersions. Part II: mixtures

et al. 2008

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We report the results of a comprehensive study of the rheological properties of a series of mixed colloid systems where the shape of one of the components has been varied systematically. Specifically we have measured the oscillatory, transient (creep) and continuous steady shear flow behaviour of a 2.5 wt% dispersion in water of a well-characterised hectorite clay modified by the addition of a series of aluminasol colloidal particles whose shape varies systematically from rod (boehmite) to platelet (gibbsite) to sphere (alumina-coated silica), all having essentially the same smallest dimension, which is similar to that of the hectorite. The particle characterisation and rheological properties of the pure components have recently been reported in Part I of this series (Soft Matter, 2007, 3, 1145. The mixtures show the same general behaviour as the pure systems, displaying a complex 'yield space' transition from an elastoviscous gel at low applied stresses to a viscous, weakly elastic, shear-thinning liquid at high stresses. The unifying theme of this work is that the addition of 0.25 wt% of the minor component in all cases results in dramatic enhancements to the dispersion rheological properties. At the same time the magnitude of this effect depends on the shape of the particles. Shear moduli, low stress viscosities and effective yield stresses all increase in the additive order rods , platelets , spheres, with enhancements for the latter being up to a factor of 500 and typically 20. At the same time the critical failure strains for the gels decreased in the same order -the strongest gels are also the most fragile in this sense. The physicochemical factors underlying this behaviour are discussed and a simple qualitative model described. While no complete explanation or model can be proposed at this stage, the study provides a quantitative model-system baseline for mixed colloidal dispersions already used for industrial applications (e.g. oilwell-drilling fluids) and suggests ways in which such fluids may be optimised and controlled.

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Gelation versus liquid crystal phase transitions in suspensions of plate-like particles

Cited by 35 publications

References 27 publications

Bioinspired assembly of surface-roughened nanoplatelets

Bioinspired assembly of surface-roughened nanoplatelets

Structure of the repulsive gel/glass in suspensions of charged colloidal platelets

Rheology modification in mixed shape colloidal dispersions. Part II: mixtures

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