Rheology of suspensions stabilized by long grafted polymers

Nommensen, P.A.; Duits, Michael H.G.; Lopulissa, J.S.; Ende, Dirk van den; Mellema, J.

doi:10.1007/bfb0118067

Cited by 20 publications

(18 citation statements)

References 16 publications

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“…All measurements were performed with a suspension of particles (coded SMD65-ps347.5) that consist of a silica core coated with a layer of end-grafted polydimethylsiloxane (PDMS) in the solvent heptane at a temperature of 25 °C. Both synthesis and characterization are elaborately reported by Nommensen et al Here we summarize these results briefly.…”

Section: Methodsmentioning

confidence: 73%

Elastic Modulus at High Frequency of Polymerically Stabilized Suspensions

et al. 2000

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The elastic moduli of polymerically stabilized suspensions consisting of colloidal silica particles coated with endgrafted PDMS (M n = 80 000) in heptane, were measured as a function of concentration. And the elastic modulus at high frequency was quantitatively described by model calculations with microscopic parameters. In the modeling of we essentially followed the method of Elliott and Russel [Elliott, S. L.; Russel, W. B. J. Rheology 1998, 42, 361]. To suit our case of strongly curved polymer layers, we made adaptations in the description of both the pair potential and hydrodynamic interactions. Anticipating that the predicted is sensitive to the modeling of the polymer brush, we explored two different models to predict the pair potential and the polymer layer thickness: a numerical self-consistent field lattice model [Wijmans, C. M.; Zhulina, E. B. Macromolecules 1993, 26, 7214] and an analytical method based on the approach of Li and Witten [Li, H.; Witten, T. A. Macromolecules 1994, 27, 449]. The polymer models were used separately in the model calculations for with the magnitude of their parameters obtained from (elaborate) characterizations of the particles. Both models result in a quantitative description of the experimental and thickness of the polymer layer.

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Section: Methodsmentioning

confidence: 73%

Elastic Modulus at High Frequency of Polymerically Stabilized Suspensions

et al. 2000

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“…Deviations from hard-sphere behavior in the high concentration range have been observed for other soft colloidal systems, such as colloids with a thick layer of grafted polymers [38,40,41], micro-gel particles [11,35,36], star polymers [42], sodium-caseinate solutions [43], and casein sub-micellar solutions [44]. The interpretation of this deviation is in general quite straight forward.…”

Section: Flow Curves and Zero-shear Viscositiesmentioning

confidence: 90%

Rheology and structural arrest of casein suspensions

Dahbi

Alexander

Trappe

et al. 2010

Journal of Colloid and Interface Science

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The rheology of milk powder suspensions is investigated up to very high concentrations, where structural arrest occurs. The main component of the milk powder investigated is casein, so that the suspensions can be regarded as casein suspensions. Four concentration regimes are identified. For effective casein volume fractions less than 0.54 the concentration dependence of the zero-shear viscosity is similar to that of hard-sphere suspensions. However, due to the elastic deformation of the caseins, the viscosity does not diverge at the hard sphere glass transition. In the volume-fraction range of 0.55-0.61 the viscosity exhibits a surprisingly weak dependence on concentration. The shape of the curve of the shear viscosity versus concentration deviates from hard sphere behavior in an unusual way, due to the observation of a region of almost constant viscosity. This concentration regime is followed by a regime where the viscosity steeply increases, eventually diverging at an effective volume fraction of 0.69. Frequency dependent rheology and diffusing wave spectroscopy measurements indicate that the suspensions are jammed for volume fractions above 0.69. Finally we found the concentration dependence of the relative zero-shear viscosity of casein suspensions to be very similar with the one of the micro-gels at volume fractions below 0.50 and above 0.55, which are know to shrink above a certain volume fraction, due to osmotic stress.

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“…It is essentially in the limit f & 1 where a description of star polymers as sterically stabilized colloidal particles holds. This polymer-colloid hybrid character of star polymers has been explored in a number of publications dealing with the structural 17,20,25,[38][39][40][41][42][43][44][45][46][47][48][49] and dynamical 17,41,42,[50][51][52][53][54][55][56][57][58][59] properties of star polymers.…”

Section: Star Polymersmentioning

confidence: 99%