Molecular modelling for investigation of material properties of graphene nanoplatelet composites

Abstract

This master’s thesis investigates the molecular modelling of material properties of graphene nanoplatelet (GNP)/epoxy composites using molecular dynamics (MD) simulations. A cross-linked epoxy matrix (DGEBF/DETDA) with embedded GNPs was constructed in BIOVIA Materials Studio using the COMPASS force field. Elastic constants were calculated via the strain fluctuation method, yielding full compliance tensors and derived Young’s moduli. Results from production runs lasting 50 ps and 100 ps were compared, showing that simulation length substantially affects predicted values, with relative errors in compliance components sometimes exceeding the mean values. While Young’s moduli (approximately 1.6–2.6 GPa) were of the same order of magnitude as experimental references (≈3 GPa at 3–4 wt% GNP), the high statistical errors highlight the need for convergence studies. Additional contributions include the development of a workflow for molecular modelling with MD and the finding that MD simulations of insufficient duration limit the accuracy of the modelling. The thesis concludes with recommendations for longer simulations and the use of high-performance computing platforms (e.g. LAMMPS or GROMACS), as well as future work on neural network surrogate models for investigating plastic material behaviour.