1 Coarse - Grained Molecular Dynamics Simulation of Polyethylene 2 Terephthalate ( PET )

9 ABSTRACT: A coarse-grained (CG) model of poly(ethylene terephthalate) (PET) was developed and 10 implemented inCGmolecular dynamics (MD) simulations of PET chainswith degree of polymerization up to 11 50. TheCGpotential is parametrized to structural distribution functions obtained fromatomistic simulations 12 [ J. Phys. Chem. B 2010, 114, 786] using an inversion procedure based on theOrnstein-Zernike equationwith 13 the Percus-Yevick approximation (OZPY) [ Phys. Rev. E 2010, 81, 061204]. The CGMD simulation of PET 14 chains satisfactorily reproduces the structural and dynamic properties from atomistic MD simulation of the 15 same systems. We report the average chain end-to-end distance and radius of gyration, relaxation time, self16 diffusivity, and zero-shear-rate-viscosity’s dependence on degree of polymerization. For the longest chains, 17 we find the scaling exponents of 0.51, 0.50, and -2.00 for average chain end-to-end distance, radius of 18 gyration and self-diffusivity, respectively. The exponents are very close to the theoretical values of entangled 19 polymer melt systems (0.50, 0.50, and -2.0). The study of entanglement in the longer chains shows that the 20 tube diameter, number ofmonomers between entanglement points and interentanglement strand length are in 21 close agreement with the reported values for an entangled PET melt.