Test of the "radical-like polymerization" scheme in molecular dynamics on the structural and shock properties of polymers

The behavior of polymer melts under shock loading is a question attracting more and more attention because of applications such as sports and car equipment. Molecular dynamics(MD) simulations are a very good tool to... [ view full abstract ]

The behavior of polymer melts under shock loading is a question attracting more and more attention because of applications such as sports and car equipment. Molecular dynamics(MD) simulations are a very good tool to characterize the microscopic response of the polymer to a shock wave. To do so, the initial configuration of the polymer melt needs to be realistic. The "radical-like polymerization" scheme [Perez et al, J. Chem. Phys. 128, 234904 (2008), Wu et al, Polymer 47,6004 (2006)] is a method to obtain near equilibrium configurations of a melt of long polymer chains. It consists in adding one neighboring monomer at a time to each growing chain. Between each polymerization step an MD run is performed to relax the new configuration. We compare the structural properties, such as end-to-end distance and radius of gyration, to other simulation and experimental results on reference polymers. We also test how details of our implementation of the "radical-like polymerization"scheme can impact or not Hugoniot curves and changes of chain configuration under shock.