This award supports theoretical and computational research and education on how long chain-like molecules or polymers, crystallize. Consider a collection of tangled wires and think about organizing them into well-ordered crystals. Such a seemingly difficult task, however, occurs naturally and readily in the real world even for the simplest polymers such as polyethylenes. In fact, most of the materials today are made from such semicrystalline polymers, which constitute a multi-billion-dollar industry. An understanding of the crystallization process of polymers is one of the longstanding research challenges in the materials world, primarily due to the haphazard and random configurations of the polymer molecules before they organize into crystals. As a result, the phenomenon of polymer crystallization is challenging with few unifying conceptual themes. This research program is geared towards development of fundamental concepts to understand how polymers crystallize and melt, using theory and modelling. A fundamental understanding of the behaviours of this important class of materials will help to design and process novel polymeric materials with enhanced benefits to our society. This project includes training graduate students in this challenging research area of tremendous societal value.
This award supports theoretical and computational research and education on how polymers crystallize. Crystallization of polymers from solutions and melts is one of the longstanding research areas in polymer science with tremendous industrial value, full of intrigue without unifying conceptual themes. A fundamental understanding of how polymer chains organize into hierarchical crystalline structures remains elusive. The most significant endowment of flexible polymer molecules is their conformational entropy. This attribute sets the crystallization and melting behaviours of polymers to be distinct from other ordering phenomena of small molecular systems. This research project is aimed to develop fundamental concepts behind polymer crystallization and melting, by accounting for conformation entropy of polymer chains and topological defects under non-equilibrium conditions. The principal investigator will employ statistical mechanics, field theory, and various simulation techniques in the development of new theories of polymer crystallization and melting. More specifically, the research project will address (a) single crystal morphology - topological defects driving sectorization in lamellae and relative stabilities of flat lamellae, hollow pyramids, scrolls, and twisted lamellae, (b) kinetics of melting and recrystallization of polymer crystals, and (c) macromolecular origin of melt-memory in polymer crystallization.
The results from the research program may have impact in the multi-billion-dollar industry of polyolefins and also in numerous applied areas such as polymer processing, and fabrication of polymeric nanomaterials. Training graduate students in this challenging research area is a strong educational component of the research program.
