(13g) Developing a Tractable Simulation of Primary Crystal Nucleation in a Polymer Melt

While semi-crystalline polymers are ubiquitous and have been studied for decades, many mysteries remain regarding the kinetics of crystallization, limiting our control of material properties and impeding future technological innovations. One especially perplexing phenomena is the so-called melt memory effect in polymer re-crystallization experiments where properties such as the nucleation rate and crystal thickness are observed to depend strongly on process history. It is widely suspected that melt memory effects are tied to the primary nucleation event in polymer crystallization, however the community is divided between two fundamental explanations. Some researchers believe that slow dynamics, primarily due to entanglement, are the root cause of memory effects in what would otherwise be a straightforward application of classical nucleation theory. However, driven by a number of intriguing theoretical and experimental results, some researchers have suggested that melt memory effects are better explained by a more sophisticated theory of primary nucleation that includes one or more intermediate metastable states. To explore the latter hypothesis, we are developing a Monte Carlo model capable of calculating the free energy surface for a nucleating crystal in a polymer melt. We will discuss our recent progress and challenges developing this model, focusing on our efforts to create a scalable, parallel Wang-Landau simulation of a polymer melt.