Revolutionary and Efficient Synthesis of Cyclic Polymers

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With thia award, the Macromolecular, Supramolecular and Nanochemistry Program of the Division of Chemistry is supporting Professors Adam Veige and Brent Sumerlin of the University of Florida to synthesize and characterize polymers that are cyclic and to establish the differerences between these polymers and their linear analogs.Plastics are often comprised of long chain-like molecules called polymers. Plastics are ubiquitous in modern life and in part are responsible for the current high standard and quality of life enjoyed by industrialized nations. Polymers have many different topologies (shapes), but most commonly they are long linear chains. Accessing this new class of polymers and determining their unique properties may create new opportunities for the development of functional materials. Through participating in this cross-disciplinary project, graduate and undergraduate students acquire a diverse set of advanced technical skills for modern inorganic and polymer synthesis and for characterization. The properties of polymers are, in part, dictated by their chain ends. Cyclic polymers inherently do not have chain ends, and as a consequence, unique physical properties arise. Investigating cyclic polymers remains a challenge even after many decades. Thus, a longstanding challenge in polymer chemistry is to synthesize cyclic polymers efficiently, with diverse compositions, high purity, high molecular weights, and from readily available monomers. This proposal addresses the challenge of synthesizing pure cyclic polymers by employing new catalyst technology developed at the University of Florida. The project involves the synthesis of the first examples of macrocyclic polyenes with high molecular weights. Of particular interest is the synthesis of the first example of cyclic polypropylene and to examine its tacticity. Another important target is cyclic polyacetylene. The parent linear polyacetylene, when doped, remains one of the highest conducting polymers known, though it has limited use since it is unstable in air and intractable. It is one of the aims of this project to investigate how the conductive properties, solubility, and stability differ for the cyclic version. Facilitated access to cyclic analogs of well-known linear polymers provides a convenient method to investigate fundamental structure-property relationships.