Seminars

Jasper van der Gucht (Wageningen University)
"Fracture of disordered (double) polymer networks : insights from coarse-grained simulations"

Fracture of materials typically occurs via the nucleation and propagation of cracks. Most polymer materials are brittle, and fracture occurs abruptly, without significant softening prior to failure. The origin of this brittle failure lies in the strong stress concentration at defects and crack tips. However, in sparsely connected fiber networks, mechanical failure may occur in a completely different way [1]. When deformed, such networks show a very heterogeneous stress distribution with emerging force chains. The continuous formation and rupture of these force chains suppresses stress concentration and can thereby prevent crack nucleation, leading to a continuous percolation-like failure. I will show extensive computer simulations that unveil how the failure of fiber networks depends on connectivity, and on properties of the individual fibers, and how the failure can go from ductile to brittle, depending on the rigidity of the network and the system size [1,2]. I will then consider double networks consisting of one polymer network embedded and interpenetrated with a second network[3]. The double network structure toughens the network significantly, and leads to a transition from brittle to ductile failure. Our simulations show different regimes of failure and allow us to pinpoint microscopic mechanisms responsible for toughening of double networks and to explain experimental findings [4,5].

REFERENCES

[1] S. Dussi, J. Tauber, J. van der Gucht, Physical Review Letters 124, 018002 (2020).
[2] F. Burla, J. van der Gucht, et al. PNAS 117, 8326 (2020).
[3] F.Burla, J. Tauber, S. Dussi, J. van der Gucht, G.H. Koenderink, Nature Physics, 15, 549 (2019)
[4] J. Tauber, S. Dussi, J. van der Gucht, Phys. Rev. Mat. 4 (2020), 063603.
[5] J. Tauber, L. Rovigatti, S. Dussi, J. van der Gucht, Macromol. 28 (2021), 8563.