Wang-Landau Simulation of the Free Energy Surface of Crystallization in a Polymer Melt*

Semicrystalline polymers comprise as much as 70% of the hundreds of million of tons of polymers produced worldwide. However, the polymer crystallization process remains imperfectly understood. Recently, there has been a lively debate in the literature concerning the applicability of classical nucleation theory to the primary nucleation process in a polymer melt. Recent experimental observations have lead several authors to propose mesomorphic phases that mediate the melt-crystal transition. To investigate these claims, we have constructed a GPU-accelerated Wang-Landau Monte Carlo algorithm that employs both configurational bias and bond breaking moves. Our algorithm has the ability to directly sample the density of states, which can be used to construct a free energy surface as a function of relevant order parameters for crystallization. Our initial results show that we are able to capture both melt and crystalline phases with speed increases of about two orders of magnitude greater than with a comparable serial algorithm.