Date of Award


Document Type



Mechanical Engineering


Polymer crystallization is a classical problem of polymer research. Many synthetic and natural polymers take the semi-crystalline form. Crystallization of polymers is a complex process associated with the partial alignment of their molecular chains. The final physical properties of semicrystalline polymers are determined by the degree of crystallinity and the size and orientation of the crystallites (nano- to micro-sized crystalline regions). Although it has been studied for many years, we still lack a fundamental understanding of the types of factors that influence the semicrystalline structure and how the structure affects the final properties. It is difficult because crystalline polymers are far from thermodynamic equilibrium, and theories usually fall short of accurately describing the process. In addition, recent experimental studies indicate a multi-stage process where the polymer chains undergo several transitions before an overall crystalline phase is fully developed, making hands-on experiments alone challenging to study this phenomenon [1].

Nanofillers with characteristic sizes smaller than tens of nanometers have been used to enhance the mechanical properties of polymers. However, the specific effect of the nanointerfaces between nanofillers and polymer chains on the nanocomposite's structural evolution and resulting mechanical properties remain largely elusive. This knowledge gap stems from two-fold challenges: (1) experimental techniques and characterizations have limited resolutions at the molecular level and nanoscale interface interactions, and (2) the involved spatial-temporal scales ranging from molecular chains, nanointerfaces, and microstructural evolutions are beyond the capability of any computational models or simulation techniques.

Therefore, this project aims to understand the nano-fillers, interfaces, and microstructures in the mechanical properties of biopolymer-based nanocomposites, which have potential in diverse applications. Specifically, the goal of my departmental honors research is to investigate the effect of nanointerfaces on the semicrystalline structure of biopolymers through molecular dynamics (MD) simulations.