• Zaccarelli, Emanuela
• Sorichetti, Valerio
• Micheletti, Cristian
• Hugouvieux, Virginie
• Rovigatti, Lorenzo
• Ninarello, Andrea
• Ruiz-Franco, José
• Kob, Walter

Abstract

The elasticity of disordered and polydisperse polymer networks is a fundamental problem of soft matter physics that is still open. Here, we report a simulation study of a model for such systems, prepared with either trivalent or tetravalent crosslinks. The networks are self-assembled via equilibrium simulations that result in an exponential strand length distribution, similar to that of experimental randomly crosslinked systems. We find that the fractal structure of the network depends on the initial density $ρ_{init}$, but that systems with the same mean valence and same $ρ_{init}$ have the same structural properties. Moreover, we compute the long-time limit of the mean-squared displacement, also known as the (squared) localization length, of the crosslinks and of the middle monomers of the strands, showing that the dynamics of long strands is well described by the tube model. Finally, we find a relation connecting these two localization lengths at high density, and connect the crosslink localization length to the shear modulus of the system.

Topics

• density
• impedance spectroscopy
• polymer
• simulation
• defect
• elasticity