Development of dissociative force field for all-atomistic molecular dynamics calculation of fracture of polymers |
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| Authors: | Kazushi Fujimoto Rajadeep Singh Payal Tomonori Hattori Wataru Shinoda Masayuki Nakagaki Shigeyoshi Sakaki Susumu Okazaki |
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| Institution: | 1. Department of Materials Chemistry, Nagoya University, Nagoya, Japan;2. Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto, Japan |
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| Abstract: | A dissociative force field for all-atomistic molecular dynamics calculations has been developed to investigate impact fracture of polymers accompanying dissociation of chemical bonds of polymer main chain. Energy of dimer molecules was evaluated as a function of both bond-length b and bond-angle θ by CASPT2 calculations, whose quality is enough to describe dissociation of chemical bonds. Because we found that the bond dissociation energy D decreases with increasing bond-angle, we employed the Morse-type function VBond(b, θ) = {D − VAngle(θ)}1 − exp{−α(b − b0) − β(b − b0)2}] where a quartic function VAngle(θ) = k1(θ − θ0) + k2(θ − θ0)2 + k3(θ − θ0)3 + k4(θ − θ0)4 . This function reproduced well the CASPT2 potential energy surface in a wide range of b and θ. The parameters have been obtained for four popular glassy polymers, polyethylene, poly(methyl methacrylate), poly(styrene), and polycarbonate. © 2019 Wiley Periodicals, Inc. |
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| Keywords: | polymer fracture bond dissociation potential function for classical AA-MD quartic function angle dependence Morse-type function |
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