Temperature dependent spectroscopic studies of HiPco SWNT composites.
Document Type Article
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Hybrid systems of the conjugated organic polymer poly (p-phenylene vinylene-co-2,5-dioctyloxy-m-phenylene vinylene) (PmPV) and HiPco SWNTs are explored using spectroscopic and thermal techniques to determine specific interactions. Vibrational spectroscopy indicates a weak interaction and this is further elucidated using Differential Scanning Calorimetry, Temperature Dependent Raman Spectroscopy and Termperature Dependent Infrared Spectroscopy of the raw materials and the cmposite. An endothermic transition is observed in the DSC of both the polymer and the 0.1% HiPco composite in the region of 60degrees centigrade. Also observed in the DSC of the composite is a doubly peaked endothern at -39 degrees and -49 degrees centigrade, which does not appear in the polymer film. The Raman of the polymer backbone upon increasing the temperature to 60 degrees centigrade shows diminished phenyl Ag modes at 1557cm and 1575 cm, with an increase in the relative intensity of the vinyl mode at 1630cm. this change in the Raman of the polymer is translated to the Raman of the composite upon increase to 60 degrees centigrate, where the spectrum becomes abruptly dominated by nanotubes. The Raman of the composite shows no change in the lower temperature regions, however infrared suggests that the transition at -39 degrees centigrade derives from an interaction with teh polymer side chains. The composite at -39 degrees centigrade shows a change in the absorption of the polymer side chain aryl-oxide linkage at 1250 cm,while Raman suggests a change to the polymer backbone configuration at 60 degrees centigrade. Implications are discussed