Molecular dynamics simulations of single polyethylene chain folding during fast quenching using all-atom and united-atom models.

Molecular dynamics simulations have been employed to investigate the folding behavior of a single linear polyethylene (PE) chain containing 1000 backbone carbon atoms under fast quenching based on all-atom and united-atom models. The single-chain folding characteristics were studied in detail for six different force fields by analyzing the evolution of chain conformations, folded structure characterisation, free energy and crystallisation. The results show that the all- chain undergoes a similar two-stage chain collapse mechanism during isothermal relaxation at = 500 K, transitioning from local collapse to global collapse into a molten globule state under different force fields.