Supramolecular Polymerizations:
A Route to Responsive Materials

Professor Stuart J. Rowan
Department of Macromolecular Science and Engineering
Case Western Reserve University

DATE: Thursday, April 15, 2004
TIME: 4:00 p.m.
PLACE: Engineering II, Room 3361

ABSTRACT

Supramolecular polymerization, i.e., the self-assembly of polymer-like materials through the utilization of the non-covalent bond, has been a developing area of research over the last decade. In that time a variety of different binding motifs have been investigated with varying degrees of success. Such supramolecular polymers potentially have a number of interesting properties: 1) they form spontaneously, without the need for an initiation process (or catalyst); 2) they are ‘dynamic’ i.e., are formed under reversible conditions; and 3) there are few termination processes possible. As a result, the degree of polymerization depends, to a large extent, on the strength of the supramolecular interaction between the monomer units. Furthermore, the equilibrating nature of these polymers allows the system to adjust and adapt to its environment, offering their possible development as responsive or self-healing materials. Such a ‘dynamic’ behavior allows for the tuning of the polymer’s properties and, in addition, may allow the development of materials, which possess good mechanical properties at room temperature while having a low melt viscosity at moderate temperatures. Such properties open up the possibility for such systems to have low energy processing and recycling costs. In this presentation we outline our initial investigations in this area which have focused on the use of nucleobase-pair and metal-ligand interactions to control the self-assembly of macromonomers into polymeric architectures. As a first step we have prepared a series of low-molecular weight macromonomer cores which contain either a nucleobase derivative or the 2,6- bis-(benzimidazolyl)pyridine (BIP) ligand attached to either end of the core. The characterization and properties of all these materials will be discussed.