Colloidal gelation with variable attraction energy

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Colloidal gelation with variable attraction energy. / Zaccone, Alessio; Crassous, Jerome; Ballauff, Matthias.

I: Journal of Chemical Physics, Vol. 138, Nr. 10, 104908, 2013.

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Zaccone, Alessio ; Crassous, Jerome ; Ballauff, Matthias. / Colloidal gelation with variable attraction energy. I: Journal of Chemical Physics. 2013 ; Vol. 138, Nr. 10.

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TY - JOUR

T1 - Colloidal gelation with variable attraction energy

AU - Zaccone, Alessio

AU - Crassous, Jerome

AU - Ballauff, Matthias

PY - 2013

Y1 - 2013

N2 - We present an approximation scheme to the master kinetic equations for aggregation and gelation with thermal breakup in colloidal systems with variable attraction energy. With the cluster fractal dimension d(f) as the only phenomenological parameter, rich physical behavior is predicted. The viscosity, the gelation time, and the cluster size are predicted in closed form analytically as a function of time, initial volume fraction, and attraction energy by combining the reversible clustering kinetics with an approximate hydrodynamic model. The fractal dimension d(f) modulates the time evolution of cluster size, lag time and gelation time, and of the viscosity. The gelation transition is strongly nonequilibrium and time-dependent in the unstable region of the state diagram of colloids where the association rate is larger than the dissociation rate. Only upon approaching conditions where the initial association and the dissociation rates are comparable for all species (which is a condition for the detailed balance to be satisfied) aggregation can occur with d(f) = 3. In this limit, homogeneous nucleation followed by Lifshitz-Slyozov coarsening is recovered. In this limited region of the state diagram the macroscopic gelation process is likely to be driven by large spontaneous fluctuations associated with spinodal decomposition. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4794695]

AB - We present an approximation scheme to the master kinetic equations for aggregation and gelation with thermal breakup in colloidal systems with variable attraction energy. With the cluster fractal dimension d(f) as the only phenomenological parameter, rich physical behavior is predicted. The viscosity, the gelation time, and the cluster size are predicted in closed form analytically as a function of time, initial volume fraction, and attraction energy by combining the reversible clustering kinetics with an approximate hydrodynamic model. The fractal dimension d(f) modulates the time evolution of cluster size, lag time and gelation time, and of the viscosity. The gelation transition is strongly nonequilibrium and time-dependent in the unstable region of the state diagram of colloids where the association rate is larger than the dissociation rate. Only upon approaching conditions where the initial association and the dissociation rates are comparable for all species (which is a condition for the detailed balance to be satisfied) aggregation can occur with d(f) = 3. In this limit, homogeneous nucleation followed by Lifshitz-Slyozov coarsening is recovered. In this limited region of the state diagram the macroscopic gelation process is likely to be driven by large spontaneous fluctuations associated with spinodal decomposition. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4794695]

U2 - 10.1063/1.4794695

DO - 10.1063/1.4794695

M3 - Article

VL - 138

JO - Journal of Chemical Physics

T2 - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 10

M1 - 104908

ER -