An experimental study of a model colloid-polymer mixture

Poon, Wilson; Selfe, J. S.; Robertson, Malcolm B.; Ilett, S. M.; Pirie, A. D.; Pusey, P. N.

doi:10.1051/jp2:1993184

Cited by 100 publications

(109 citation statements)

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“…The particles forming the glassy cage tend to stick together, thereby creating openings in the collective cage around a central particle which have to be filled by increasing the critical colloid density. We suggest that the recrystallization of glass samples at high densities upon addition of short polymers, reported in [8], is explained by this shift of the glass transition density to higher values. Moreover, the MCT glass transition line was observed to lie parallel to the DFT fluid-solid freezing transition at high temperatures in the AHS phase diagram.…”

Section: Discussionmentioning

confidence: 59%

“…It is by now well established that when the range of the colloidal attraction is decreased the phase diagram undergoes a progression from gas-liquid-solid to fluid-solid coexistence, the latter with a subcooled critical point which is metastable with respect to fluid-solid coexistence [1][2][3][4][5]. Numerous experimental studies show that suspensions often form incompletely equilibrated solids with the appearance of gels where one expects a fluid-solid [6][7][8][9][10][11][12][13][14] or gas-liquid [15] phase separation from equilibrium theory. The systems studied include mixtures of colloids and non-adsorbing polymer [6][7][8][9][10][11] and sterically stabilized colloids in marginal solvents [12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

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Nonergodicity transitions in colloidal suspensions with attractive interactions

1999

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The colloidal gel and glass transitions are investigated using the idealized mode coupling theory (MCT) for model systems characterized by short-range attractive interactions. Results are presented for the adhesive hard sphere and hard core attractive Yukawa systems. According to MCT, the former system shows a critical glass transition concentration that increases significantly with introduction of a weak attraction. For the latter attractive Yukawa system, MCT predicts low temperature nonergodic states that extend to the critical and subcritical region. Several features of the MCT nonergodicity transition in this system agree qualitatively with experimental observations on the colloidal gel transition, suggesting that the gel transition is caused by a low temperature extension of the glass transition. The range of the attraction is shown to govern the way the glass transition line traverses the phase diagram relative to the critical point, analogous to findings for the fluid-solid freezing transition.

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Section: Discussionmentioning

confidence: 59%

Section: Introductionmentioning

confidence: 99%

Nonergodicity transitions in colloidal suspensions with attractive interactions

1999

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“…If polymer partitioning is taken into account [18] a three-phase equilibrium region in the latter phase diagram is found. These predicted phase diagrams have recently been confirmed experimentally including the existence of a three-phase gas liquid-crystal region [, [1][2][3].…”

Section: Introductionmentioning

confidence: 71%

“…Mixtures of colloidal hard spheres and non-adsorbing polymer show interesting phase behavior, as several experimental studies have revealed [1][2][3][4][5][6][7][8][9][10][11][12][13]. The starting point for theoretical models describing this phase behavior is the notion that the polymers are excluded from a depletion zone surrounding the particles, since they cannot penetrate the colloidal spheres [14,15].…”

Section: Introductionmentioning

confidence: 99%

Fluid-fluid phase separation in colloid-polymer mixtures studied with small angle light scattering and light microscopy

Verhaegh

Duijneveldt

Dhont

et al. 1996

Physica A: Statistical Mechanics and its Applications

104

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Mixtures of colloidal silica spheres and polydimethylsiloxane in cyclohexane with a colloid-polymer size ratio of about one were found to phase separate into two fluid phases, one which is colloid-rich and one which is colloid-poor. In this work the phase separation kinetics of this fluid-fluid phase separation is studied for different compositions of the colloid-polymer mixtures, and at several degrees of supersaturation, with small angle light scattering and with light microscopy. The small angle light scattering curve exhibits a peak that grows in intensity and that shifts to smaller wave vector with time. The characteristic length scale that is obtained from the scattering peak is of the order of a few p.m, in agreement with observations by light microscopy. The domain size increases with time as t 1/3, which might be an indication of coarsening by diffusion and coalescence, like in the case of binary liquid mixtures and polymer blends. For sufficiently low degrees of supersaturation the angular scattering intensity curves satisfy dynamical scaling behavior.

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“…When the colloids are close enough their depletion zones overlap, causing an unbalanced osmotic force. This results in an attractive interaction between the colloidal particles, the range and depth of which can be tuned by the diameter ( p ) and the volume fraction ( p ) of the polymer, giving rise to di erent types of phase diagrams [3][4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Transient gels in colloid–polymer mixtures studied with fluorescence confocal scanning laser microscopy

Verhaegh

Asnaghi

Lekkerkerker

1999

Physica A: Statistical Mechanics and its Applications

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We study the structure and the time evolution of transient gels formed in colloid-polymer mixtures, by means of uorescence Confocal Scanning Laser Microscopy (CSLM). This technique is used in conjunction with novel colloidal silica particles containing a uorescent core. The confocal micrographs reveal that there exist large di erences in the local structure within a single system. At a given time there are regions where the gel structure consists of alternating patterns of colloid-rich and colloid-poor regions with a characteristic length scale and regions where the gel structure becomes disrupted by the formation of fractures. The number of fractures increases with time. It is speculated that the increase of the number of fractures leads to a weakening of the strength of the gel such that it eventually collapses under gravity.

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An experimental study of a model colloid-polymer mixture

Cited by 100 publications

References 0 publications

Nonergodicity transitions in colloidal suspensions with attractive interactions

Nonergodicity transitions in colloidal suspensions with attractive interactions

Fluid-fluid phase separation in colloid-polymer mixtures studied with small angle light scattering and light microscopy

Transient gels in colloid–polymer mixtures studied with fluorescence confocal scanning laser microscopy

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