Robert S. Hoy, Nikos Ch. Karayiannis
We develop a simple coarse-grained bead-spring polymer model exhibiting competing crystallization and glass transitions. For quench rates slower than the critical nucleation rate $|\dot{T}|_{crit}$, systems exhibit a first-order crystallization transition below a critical temperature $T=T_{cryst}$. Such systems form close-packed crystallites of FCC and/or HCP order, separated by domain walls, twin defects, and an amorphous interphase. The size of amorphous regions grows continuously as the quench rate $|\dot{T}|$ increases, producing nearly amorphous structure for $|\dot{T}|>|\dot{T}|_{crit}$. Our model exhibits many features observed in recent studies of crystallization of athermal polymer packings, but also critical differences arising from the softness of the pair interactions and the thermal nature of the phase transition. The model is considerably more computationally efficient than other recent crystallizable coarse-grained polymer models; while it sacrifices some features of real semicrystalline polymers (such as lamellar structure and chain disentanglement), we anticipate that it will serve as a useful model for studying generic features related to semicrystalline order in polymer solids.
View original:
http://arxiv.org/abs/1303.5494
No comments:
Post a Comment