TY - JOUR

T1 - A master curve for the onset of shear induced restructuring of fractal colloidal aggregates

AU - Becker, Volker

AU - Briesen, Heiko

N1 - Funding Information:
We acknowledge the financial support of the German Science Foundation (DFG priority program SPP 1273).

PY - 2010/6

Y1 - 2010/6

N2 - Colloidal aggregates exposed to shear flow exhibit a size-dependent qualitative behavior [Becker et al. JCIS, 339, 362-372, 2009]. Under the same flow conditions small aggregates rotate like rigid bodies, whereas larger aggregates change their structure and even bigger aggregates break. In this study the transition from the rotational regime to the restructuring regime is investigated by DEM simulations. We applied a model for tangential interaction, capable of supporting bond-bending moments and torsional torques [Becker, Briesen, Phys. Rev. E, 78, 2008, 061404]. The probability for an aggregate to be affected by restructuring changes with the number of primary particle from zero to one in a small interval. The probability becomes a master curve being independent of the shear flow and the interparticle interactions if it is represented as a function of the relative deviation from the critical particles number, i.e. the number of primary particle where the probability of restructuring is equal to 0.5. Investigating the dependency of the critical particle number on the shear rates reveals power law relations which adequately represents the data. The exponents in the power law relations can particularly obtained from a fractal scaling argument.

AB - Colloidal aggregates exposed to shear flow exhibit a size-dependent qualitative behavior [Becker et al. JCIS, 339, 362-372, 2009]. Under the same flow conditions small aggregates rotate like rigid bodies, whereas larger aggregates change their structure and even bigger aggregates break. In this study the transition from the rotational regime to the restructuring regime is investigated by DEM simulations. We applied a model for tangential interaction, capable of supporting bond-bending moments and torsional torques [Becker, Briesen, Phys. Rev. E, 78, 2008, 061404]. The probability for an aggregate to be affected by restructuring changes with the number of primary particle from zero to one in a small interval. The probability becomes a master curve being independent of the shear flow and the interparticle interactions if it is represented as a function of the relative deviation from the critical particles number, i.e. the number of primary particle where the probability of restructuring is equal to 0.5. Investigating the dependency of the critical particle number on the shear rates reveals power law relations which adequately represents the data. The exponents in the power law relations can particularly obtained from a fractal scaling argument.

KW - Colloid

KW - Colloidal aggregates

KW - Discrete element method

KW - Interaction forces

KW - Restructuring

UR - http://www.scopus.com/inward/record.url?scp=77952542210&partnerID=8YFLogxK

U2 - 10.1016/j.jcis.2010.02.015

DO - 10.1016/j.jcis.2010.02.015

M3 - Article

C2 - 20202643

AN - SCOPUS:77952542210

SN - 0021-9797

VL - 346

SP - 32

EP - 36

JO - Journal of Colloid and Interface Science

JF - Journal of Colloid and Interface Science

IS - 1

ER -