NER: Polymer Nanowires Synthesized on a Flat Surface Via a Surfactant Template

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Nanoscale materials offer many potential technological applications due to the unusual properties inherent in these materials compared to their traditional macroscale analogues. Conducting polymers are prime targets for nanoscale synthesis as their conductivity is greatly enhanced by highly oriented morphologies. In this proposal, The PI's show for the first time that oriented polyaniline (PANI) nanowires, with almost uniform radii, have been oxidatively synthesized on highly ordered pyrolytic graphite (HOPG) and on mica using anadsorbed surfactant template. They have also synthesized similar structures, but not as ordered, using polypyrrole. The dimensions of the synthesized structure vary depending on the substrate. If a way can be determined to produce conducting nanowires with almost uniform radii so that their center-to-center distances are regular and controllable, then this would have substantial impact in many areas, particularly in the microelectronics industry.The important technological discovery that has allowed them to make these advances is the fact that adsorbed monolayers of surfactant can form very unique structures at the solid-liquid interface. The type of structures range from cylinders, spheres and flat bilayers on hydrophilic surfaces, to half cylinders, half spheres and monolayers on hydrophobic surfaces. Using the results of work done by others, they were able to choose a specific surfactant structure as a patterning template. Their experiments have been successful, in the specific case of adsorbed half-cylinders the resulting film also has what appears to be a half-cylinder morphology for certain polymers and surfaces. The dimensions of the fillers have been measured to be between 50 and 100 nm in diameter, and as long as 150 microns.This exciting new discovery and the work described in this grant have all been completed over the last 4 months. Although AFM micrographs clearly support their claims, their understanding of some critical issues is not complete. For example, the structures vary significantly in dimension (height and width) depending on the substrate and monomer that is used. The wires coalesce; one of the most important issues is to understand why these wires coalesce, and determine, if possible, a way to reduce or arrest coalescence. They know almost nothing about the properties of these nanowires, including their conductivity, and clearly the properties of the wires is extremely important. This grant will enable them to explore all of these issues and help them to achieve the ultimate goal, the synthesis of fully dispersed nanowires oriented in one direction over very large length scales.