Simulation study of the order formation dynamics in the melt crystallization of flexible chain molecules induced by rigid molecular nuclei

Order formations in the crystallization processes of flexible chain molecules with regard to the nucleation effect of rigid crystalline molecules have been studied by means of molecular dynamics simulations. When the short polymer melts consist of complete flexible chains, no orientation order was observed under cooling. However, additives of rigid molecules induce the crystallization in the entire system. The time evolutions of the local and global orientation orders were examined at different concentrations of the rigid molecular nuclei. The local orientation order of flexible chains emerges sharply at a certain concentration threshold and it becomes nearly constant in the high concentration region. In the meantime, the global orientation order takes maximum values near this concentration threshold and it gradually decreases with the increase of concentration of rigid molecular nuclei. The comparison of the scaled time evolution curves reveals that the ordering dynamics during the crystallization are strongly influenced by the concentration of rigid molecular nucleating agents. (C) 2003 American Institute of Physics.