MSE Seminar Series: Shape-Symmetry Incommensurate Polymer Crystals
Friday, November 8, 2019
2108 Chem/Nuc bldg
Speaker: Christopher Li, MSE Professor @ Drexel Univeristy, PA
Title: Shape-Symmetry Incommensurate Polymer Crystals
Crystallization is ubiquitous in nature and semicrystalline polymers are of crucial importance in our daily life. Because of their long chain nature, polymers crystallize via a complex pathway, leading to profound metastable states and morphologies. This talk will focus on polymer crystals whose shape is incommensurate with three-dimensional translational symmetry. Examples are helix, hollow tubes and spheres. Not only can this shape-symmetry incommensurateness arise from the intrinsic characteristics of the crystal such as unbalanced chain folding and/or local stress, it also can be imparted by nanoscale confinement. Both cases will be discussed, and emphasis will be given to the formation mechanism, associated properties and possible applications of these unique polymer single crystals.
Dr. Li is a Professor in the Department of Materials Science and Engineering at Drexel University. He received his B.S. degree in Polymer Chemistry from the University of Science and Technology of China in 1995 and his Ph.D. in Polymer Science from the University of Akron in 1999. His research interests center on the structure and morphology of polymers and soft materials. He is a Fellow of the American Physical Society and the North American Thermal Analysis Society.