Molecular dynamics simulation of stretch-induced crystallization of star polymers as compared to their linear counterparts

The linear and star polyethylene during static crystallization and stretch-induced crystallization has been investigated by molecular dynamics simulations. The findings demonstrate that the branching point of the star polymer system does not participate in crystallization, and the crystallization ability of the segments near the branching point and at the end of the chains is inferior. Due to the existence of branching points, the mobility and conformational extension of chain segments are weak, and the entanglement degree is higher than that of linear systems. For stretch-induced crystallization, stretching promotes the extension of molecular chains and arranges them along the stretching direction. The crystal nucleation and growth in linear and star polymer systems are significantly faster than in static crystallization. The mobility of the chain segments close to the branching point is partially enhanced by stretching, while the branching point still substantially affects the chain conformation and segment orientation. It is worth mentioning that we have verified some crucial results that cannot be observed in the experiments at the microscopic scale.