Project title: Reduced order modeling of polyolefin tacticity for morphology control
This postdoctoral position is with Professor Martha Grover Gallivan and Professor Pete Ludovice at the School of Chemical & Biomolecular Engineering at Georgia Tech. The ideal candidate for this position will have a research background in process systems engineering or molecular modeling. Some knowledge of polymer chemistry or polymer physics is also desirable. The position is for one year with the possibility of extension, and the start date could be as early as January 1, 2009. For applicants attending the AIChE Annual Conference, applications received before the meeting will be considered for interviews at the meeting. Funding for this project is provided by the American Chemical Society Petroleum Research Fund.
Crystallization of polyolefins depends strongly on tacticity, or arrangement of atoms along the polymer backbone. Qualitatively, it is understood that when atoms switch sides, the greater disorder reduces crystallization. Molecular dynamics (MD) simulations could quantify this relationship, except it is not computationally feasible to equilibrate sufficiently large systems. Coarse-grained bead-spring models have been proposed to reduce the computation, but in polyolefins like polyvinylchloride and polystyrene, averaging over the smallest length-scales has failed to produce useful models due to the importance of tacticity on crystallization.
There are two scientific objectives in this project. First, polyolefin coarse-graining will be formulated in the language of coordinate transformations and model reduction, to assess the applicability in MD. Model reduction tools will also be modified and extended as required by the mathematical structure of the MD simulations. The second objective is to quantify the dominant dynamics in polyolefin crystallization—these design principles can then be used to develop and select catalysts to produce polyolefins with desired tacticity.
The polymer physics community has articulated the need for more systematic tools for coarse graining. This research will provide new tools to bridge the length-scales from molecular detail to macroscopic properties. The model reduction approach should enable improved understanding, design, and control of polyolefin processing.
Martha Grover (formerly Gallivan)
Chemical & Biomolecular Engineering
Georgia Institute of Technology