Designing two or more self-organizing mechanisms into a single polymer chain—such as crystallization of one block and repulsion between unlike blocks—yields both morphological richness and kinetic complexity.  In crystallizable block copolymers, the final structure and properties can be governed by nanophase separation in the melt, block crystallization, or a combination of the two dictated by the processing history.  However, even when the block copolymer forms a homogeneous, low-viscosity melt, the block copolymer architecture can still exert substantial control over the nanoscale structure.  For example, by attaching an amorphous block of predetermined length to the crystallizable chain, we can induce the crystallizable block to fold a precise number of times, thus precisely tuning the crystal thickness (and hence melting point) thermodynamically. We are currently investigating crystalline-amorphous block copolymers derived from ring-opening metathesis polymerization (ROMP), which permits the synthesis of a crystallizable block free from chain defects, and by a hybrid ROMP-anionic polymerization strategy.  In such high-crystallinity materials, a tight coupling between microdomain and crystallite orientation is readily achieved.  In addition, we have synthesized triblock copolymers with crystalline endblocks, and pentablocks with crystalline and glassy outer blocks, in an approach to design solvent-resistant, easily processed thermoplastic elastomers.



Richard A. Register is Professor and Chair of the Department of Chemical Engineering at Princeton University, and Director of the Princeton Center for Complex Materials, a broad-based Materials Research Science and Engineering Center funded by the National Science Foundation.  His research interests revolve around micro- and nanostructured polymers, such as block copolymers, polymer blends, semicrystalline polymers, and ionomers, ranging across their physics, synthesis, characterization, and applications.  He was named a Fellow of the APS in 2001, and received the Charles M.A. Stine Award from the AIChE in 2002.  He chaired the APS’s Division of Polymer Physics in 2004-2005, served as a Director of the AIChE’s MESD (2004-2006), and was a Volume Organizer for the Materials Research Society’s MRS Bulletin in 2007.


[loc] MEM Seminar Room (Curtis 162) [/loc]