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DY: Fachverband Dynamik und Statistische Physik
DY 36: Complex Fluids and Colloids V (joint session DY/BP/CPP)
DY 36.3: Talk
Wednesday, March 9, 2016, 10:30–10:45, H47
Viscoelastic properties of marginal networks in a solvent — •Matthew Dennison and Holger Stark — Institut für Theoretische Physik, Technische Universität Berlin, 10623 Berlin, Germany
Elastic networks that are at the margins of mechanical stability are known to exhibit an anomalously large resistance to deformation which is highly sensitive to applied forces and fields. While many previous studies have examined the static properties of such networks, relatively little is known about their dynamical behavior. Using a hybrid molecular dynamics and multi-particle collision dynamics simulation technique, we have studied how hydrodynamic interactions affect the stiffening behavior of marginal networks.
We show how the properties of the filaments making up the network, as well as the properties of the solvent it is immersed in, can affect the response of marginal networks to shear. We find that the network is less stiff when hydrodynamic interactions are present than when they are not. The network shear modulus scales as G′∼ωαc, with a critical stiffening exponent αc that can be controlled by varying the network concentration relative to that of the solvent. Our results show that this behavior arises due to the solvent aiding the relaxation of the network and suppressing the network non-affinity, with the system deforming more affinely when hydrodynamic interactions are maximized. Finally, we show how thermal fluctuations can suppress this observed stiffening behavior.