(31c) Free Energy Surfaces for Homogeneous Nucleation in a Polymer Melt

Although semicrystalline polymers are a staple of our everyday lives, details of how homogeneous nucleation occurs remains controversial. For example, several experimental and theoretical observations indicate deviations from our conventional understanding of classical nucleation theory. Some of this recent evidence suggests the presence of stable or metastable intermediate states and asynchronous ordering processes that mediate the melt to crystalline transition. To better understand the multifaceted nature of this transition, we are using Monte Carlo tools including Wang-Landau and Extended Ensemble Density of States (EXEDOS) simulations to build free energy diagrams with respect to various crystallization order parameters. Our simulations utilize advanced bond breaking moves and GPU acceleration to improve sampling. We will discuss our calculations of these free energy surfaces, the challenges with this approach, and their implications for the outstanding controversy surrounding nucleation in semicrystalline polymers.

We acknowledge support from the ACS PRF (59244-DN16), BYU’s Board of Trustees, and BYU’s Office of Research Computing.