TY - JOUR

T1 - Elucidating atomistic mechanisms underlying water diffusion in amorphous polymers

T2 - An autonomous basin climbing-based simulation method

AU - Bahtiri, Betim

AU - Arash, Behrouz

AU - Rolfes, Raimund

N1 - Funding Information: This work originates from the following research project: “Challenges of industrial application of nanomodified and hybrid material systems in lightweight rotor blade construction” (“HANNAH - Herausforderungen der industriellen Anwendung von nanomodifizierten und hybriden Werkstoffsystemen im Rotorblattleichtbau”), funded by the Federal Ministry for Economic Affairs and Energy, Germany . The authors wish to express their gratitude for the financial support. The authors acknowledge the support of the LUIS scientific computing cluster, Germany, which is funded by Leibniz Universität Hannover, Germany , the Lower Saxony Ministry of Science and Culture (MWK), Germany and the German Research Council (DFG) .

PY - 2022/9

Y1 - 2022/9

N2 - Conventional molecular simulations of diffusive molecules in amorphous polymers lead to discrepancies in understanding diffusion mechanisms at low temperatures due to the short timescales of the simulations. This work proposes a combined scheme of the autonomous basin climbing (ABC) method accompanied with kinetic Monte Carlo and reactive molecular dynamics (MD) simulations to investigate water molecules’ diffusion pathways in amorphous epoxy resins across a wide range of temperatures. The ABC method, along with a reactive force field, provides an accurate potential energy surface sampling approach to elucidate diffusion mechanisms affected by hydrogen bonding interactions between water molecules and an epoxy network. The simulation framework allows the capture of thermal effects on the diffusion coefficients and offers a predictive simulation tool for predicting diffusion coefficients of water molecules in amorphous polymers. The simulation results show that the activation energy of the diffusion coefficient is in agreement with experimental data. The proposed simulation framework not only estimates kinetic properties of water diffusion in epoxy resins that are consistent with experimental observations, but also provides a predictive tool for studying the diffusion of small molecules in other amorphous polymers.

AB - Conventional molecular simulations of diffusive molecules in amorphous polymers lead to discrepancies in understanding diffusion mechanisms at low temperatures due to the short timescales of the simulations. This work proposes a combined scheme of the autonomous basin climbing (ABC) method accompanied with kinetic Monte Carlo and reactive molecular dynamics (MD) simulations to investigate water molecules’ diffusion pathways in amorphous epoxy resins across a wide range of temperatures. The ABC method, along with a reactive force field, provides an accurate potential energy surface sampling approach to elucidate diffusion mechanisms affected by hydrogen bonding interactions between water molecules and an epoxy network. The simulation framework allows the capture of thermal effects on the diffusion coefficients and offers a predictive simulation tool for predicting diffusion coefficients of water molecules in amorphous polymers. The simulation results show that the activation energy of the diffusion coefficient is in agreement with experimental data. The proposed simulation framework not only estimates kinetic properties of water diffusion in epoxy resins that are consistent with experimental observations, but also provides a predictive tool for studying the diffusion of small molecules in other amorphous polymers.

KW - Autonomous basin climbing

KW - Epoxy resins

KW - Kinetic Monte Carlo

KW - Reactive molecular dynamics

KW - Water diffusion

UR - http://www.scopus.com/inward/record.url?scp=85132425322&partnerID=8YFLogxK

U2 - 10.1016/j.commatsci.2022.111565

DO - 10.1016/j.commatsci.2022.111565

M3 - Article

AN - SCOPUS:85132425322

VL - 212

JO - Computational materials science

JF - Computational materials science

SN - 0927-0256

M1 - 111565

ER -