Physical Sciences and Mathematics Commons^™

Understanding Dynamics Of Polymers Under Confinement: A Molecular Dynamics And Neutron Scattering Study, Supun Samindra Kamkanam Mohottalalage

All Dissertations

The current study probes the structure, dynamics, and rheological behavior of associating polymers including ionomers in melts and solutions as well as conjugated polymers confined into nanoparticles, using molecular dynamics (MD) simulations and neutron scattering techniques. The study focuses on two families of associative polymers, ion containing macromolecules and conjugated polymers.

Polymers that consist of ionizable groups along their backbone found uses in a broad range of applications. Examples include light weight energy storage and generation systems, and biomedical applications, where the polymers act as ion exchange membranes, and actuators. The ionic groups tend to form clusters that are in …

Development Of Improved Torsional Potentials In Classical Force Field Models Of Poly (Lactic Acid), James Mcaliley

All Dissertations

In this work, existing force field descriptions of poly (lactic acid), or PLA, were improved by modifying the torsional potential energy terms to more accurately model the bond rotational behavior of PLA. Extensive calculations were carried out using density functional theory (DFT), for small PLA molecules in vacuo, and also using DFT with a continuum model to approximate the electronic structure of PLA in its condensed phase. From these results, improved force field parameters were developed using a combination of the OPLS and CHARMM force fields. The new force field, PLAFF2, is an update to the previously developed PLAFF model …