Uncertainty analysis of the molecular dynamics method for simulations of sulfonated poly ether ether ketone proton exchange membrane in fuel cells

Molecular dynamics (MD) simulations have become a standard tool for logical interpretation of proton exchange membrane (PEM) performance. However, it has several parameters that affect the accuracy and reliability of results. Considering the most prevalent, we explore uncertainty analysis of chain configurations, thermostats, ensembles, and force fields for simulations of sulfonated poly ether ether ketone PEM. In order to choose proper chains and monomers number, total solubility parameter and density are evaluated. The mean square displacement of proton and temperature variances are determined, revealing the Berendsen thermostat as appropriate temperature controllers (11 & Aring;2 and 9.478 K2, respectively). After choosing proper ensembles combination, COMPASSII, COMPASSIII, and DREIDING force fields are compared, using glass transition temperature (Tg) and proton conductivity. Tg values of DRIEDING model (461 K) are in good agreement with experimental results (458 K), while conductivities of COMPASSIII model show better consistency (16.6 mS.cm-1 vs. 18.0 mS.cm-1). Therefore, parameters selection depends on the target simulation analysis.