Frontiers in “Functional Polymers: A Symposium in Honor of Prof. S. D. Worley”

Abstracts

Kenneth J. Wynne, (Virginia Commonwealth University)

“Polyoxetane and Poly(co-oxetanes): Unexpected and Unprecedented Surface Science.*”
Polyoxetanes are polyethers or formally 2,2’-substituted-1,3-propylene oxides. Polyoxetane telechelics 1 may be represented as P[AB], where A and B are repeat units with differing side chains. These telechelics are incorporated into polyurethanes and used as polymer surface modifiers. As an example, polyurethanes were prepared with P[AB] soft blocks where A = a semifluorinated “chaperone” or PEG-like side chain and B = alkylammonium side chains. At 2wt% in a conventional polyurethane, two of the surface modifiers effect 100% kill of a 107 CFU/ml aerosol challenge of Gram +/- pathogenic bacteria in 30 min. The effectiveness of the new modifiers is due in part to surface nano-topology and spatial distribution of alkylammonium groups mimicking naturally occurring biocidal peptides such as the magainins and cecropins. Other co-polyoxetane surface science will be presented including (a) novel contraphilic wetting (wet surface hydrophobic; dry surface hydrophilic) and (b) a semicrystalline polyoxetane (1, A = B = CF3CH2OCH2-) that spontaneously develops a topologically complex surface which becomes more hydrophobic (106°®140°) with time.

* The author thanks the National Science Foundation, Division of Materials Research for support of this research.

Jeff Williams, (HaloSource Incorporated)

“Taking a functional polymer from the benchtop to the consumer marketplace: a commercialization odyssey.”
At the core of HaloSource Incorporated's technology portfolio is a set of discoveries from the Auburn University laboratories of Professor Dave Worley. The creativity and originality of the chemistry are self-evident, but developing and implementing the exclusive rights acquired by the company have involved a long and tortuous path to the marketplace. Punctuated by exhilarating breakthroughs, the process posed exhausting demands on patience and persistence--- lasting just about as long as Odysseus's journey home after the sack of Troy--- and it has been equally replete with diversionary temptations, stormy challenges, and crushing disappointments. This presentation, by a survivor, will illustrate both the Odyssey and its outcome: successful commercialization in forms that promise to impact the availability of safe water to many people in the developing world. The technology is now showing signs of remarkable versatility in the face of urgently needed improvements in water quality, world-wide, and its characteristics are emerging as nice matches for consumer needs at all levels. The peculiarities and idiosyncracies of rechargeable hydantoinylated polystyrene particles as a means of eliminating water-borne infectious contaminants will be displayed, and the roles that the Auburn inventors have played in realizing the potential of these novel polymers will be acknowledged, with examples.

Gang Sun, (University of California, Davis)

“Halamine Chemistry: Polymeric Cyclic to Polymeric Acyclic Structures”
N-halogenated polyamides were first reported as reactive N-halamines in 1960s but without much further applications since then mostly due to the fact that the polymers are lack of stability and easy to hydrolyze in water. The major development of halamine structures as biological and chemical reagents occurred in the past twenty years, thanks to the pioneering work done by Professor Worley at Auburn University. The demonstrated stable, powerful and rechargeable biocidal functions of cyclic halamine structures have greatly stimulated the study of halamine chemistry, evidenced by applications in water disinfection to biological and chemical protective textiles. Because of the insoluble and stable structures, polymeric cyclic halamines are particularly attractive in preparation of rechargeable biocidal products, and the potential demands are extremely high currently and possibly in the future. Most cyclic halamines are based on heterocyclic compounds containing nitrogen atoms that possess specific structural features of stabilizing the halamine bonds. However, these structures are relatively limited and many of them costly to prepare, particularly with additional functional groups for polymerization, which significantly limits the development of biocidal polymers. Based on the same principle of stable halamine structures, acyclic compounds such as acrylamide and methacrylamide were found capable of becoming halamines. These vinyl compounds are inexpensive and convenient to use in chemical modification of many polymers. This presentation will provide a review of the development of polymeric halamines from cyclic structures to acylic structures, and from copolymerization to surface grafting and then to melt reactive extrusion processes.

Thomas H. Epps, (University of Delaware)

“Block Copolymers: A Feasible Route to Generating Functional Nano-materials”
Soft materials, such as polymers, colloids, surfactants, and liquid crystals, are a technologically important class of matter employed in a variety of applications. One sub-class of soft material, block copolymers, provides the opportunity to design materials with attractive chemical and mechanical properties based on their ability to assemble into periodic structures with nanoscale domain spacings. Several applications for block copolymers currently under investigation in my group include battery and fuel cell membranes, analytical separations membranes, nanotool templates, precursors to electronic arrays, and drug delivery vehicles. To enable the wide-spread use of block copolymers for these materials, several problems must be overcome such as: predicting multiblock copolymer phase behavior, inducing long-range order, eliminating grain boundaries and other defects, understanding thin film behavior, and characterizing polymer interactions with their environment. One area of recent progress in the group focuses on the behavior of self-assembled polymer systems doped with various salts. We believe that these systems will enable us to overcome many of the limitations found in current ion-conduction materials, including poor mechanical integrity, poor temperature stability, non-uniform pore sizes, and poor chemical compatibility.

Kenneth R. Carter, (University of Massachusetts Amherst)

“Patterning of Electronic and Optical Organic Materials”
The focus of this study is the synthesis of new polymer brush systems in combination with nanoimprint lithography of useful patterns and structures. First we have examined the formation of polymeric brushes of two different systems, polyfluorenes and polythiophenes. Preliminary studies have demonstrated that various metal catalyzed polycondensation reactions can be performed from appropriately decorated polymer surfaces. We have created new surface active tethering groups that facilitate the attachment of polymer chains to imprinted patterned polymer layers. We have studied the incorporation of these tethering groups into our imprinted surfaces by XPS, IR and UV spectroscopy. Nanocontact molding imprint lithography (NCM) of thin films is an important lithographic techniques and shows great promise in the ability to transfer nanoscale patterns in an efficient, economic fashion. The NCM imprint techniques allow us to pattern features as small as 50 nm. When combined with microwave heating we are able to generate covalently attached polyfluorene brush layers as thick as 33 nm to patterned areas.