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Numerical Study of Soft Colloidal Nanoparticles Interaction in Shear Flow
journal contribution
posted on 2018-11-26, 00:00 authored by José
Francisco Wilson, Martin Kroupa, Juraj Kosek, Miroslav SoosThe
mechanical behavior of nanoparticle assemblies depends on complex
particle interactions that are difficult to study experimentally.
Depending on the nanoparticle morphology, these interactions could
lead to adhesive and elastic–plastic behavior during contact
deformation. The aim of this research is to study the effect of contact
interactions between polymer nanoparticles and their impact on the
macroscopic properties of formed aggregates. For this purpose, the
discrete element method (DEM) was used to develop an interaction model
combining elastic–plastic deformation and adhesion to study
the behavior of spherical polymeric nanoparticles. Initially, a pair
of particles interacting in the normal direction was simulated to
evaluate the effect of adhesion and plastic deformation in the pull-off
force of the contact. Based on these results, the simulations were
extended to a dispersed system of nanoparticles, in which multibody
interactions become dominant. Considering the aggregation between
the nanoparticles induced by a shear flow, we performed an analysis
of the number of aggregates and aggregates size in time to characterize
the strength of clusters formed during the process. The simulation
results showed that the interaction strength upon breakage of the
clusters, correlating with the aggregates size, depends on the nanoparticle’s
softness. In this way, we verified that the type of contact interaction
directly influences the macroscopic mechanical response of nanoparticle
assemblies. Therefore, our model represents a new way of predicting
the mechanical behavior of polymer nanoparticle systems and of optimizing
it by adjusting primary particle properties.