Polyacetylene nanostructured

Polyacetylenes intended as intermediates in synthesis of, especially, [18] annulene have been the major growth area in academic explosion from the 5th to the 6th edition of this handbook. No injuries and negligible damage have resulted, doubtless as much due to the care of the researchers as the often limited power of the compounds. Annulenes do not yet seem to have resulted even when they should be the initial decomposition product, implying that they will not be very stable themselves. Related compounds are now deliberately being caused to explode in hopes of preparing carbon nanostructures. 

Before 1985, six crystalline forms of carbon were known two forms of graphite, two forms of diamond, and chaoit and carbon (VI) discovered in 1968 and 1972, respectively. In addition a number of almost pure amorphous forms exist, such as polyacetylene (7.60) and cumulene (7.61) and recently a number of interesting nanostructured forms of carbon have been produced (Section 15.8). The year 1985 marked the discovery of the fullerenes, which represent the only truly pure molecular form of carbon, are produced under very extreme conditions as carbon vapour condenses in an atmosphere of an inert gas such as helium. Harold Kroto s interest in this chemistry originated with microwave spectroscopic studies of the atmosphere of stars and interstellar dust clouds. Kroto wanted to try to reproduce in the laboratory spectra of carbon... 

FIGURE 16.2 SEM images o (a) polyacetylene nanofiber ropes. (From Park, J.H., Electronic and scanning tunneling spectroscopic studies of conducting polymer nanostructures Polyacetylene nanofibers, PPV nanotubes and MEH-PPV nanowires, Ph.D. thesis, Seoul National University, Seoul, 2004.) (b) R-helical polyacetylene nanofiber ropes. (From Akagi, K., Unpublished data, 2004.)... 

FIGURE 16.4 I-V characteristics of iodine doped PA nanofiber. Znsef shows scanning force microscope image of PA nanofiber on top of Pt electrodes (with 100 nm separation). Typical diameter of PA nanofiber is 16-20 mn (From Park, J.G., et al. Synth. Met., 119, 53, 2001 and Park, J.G., Electrical transport properties of conducting polymer nanostructures Polyacetylene nanofiber, polypyrrole nanotube/nanowire, Ph.D. thesis, Seoul National University, Seoul, 2003.). 

Park, J.H. 2004. Electronic and scanning tunneling spectroscopic studies of conducting polymer nanostructures Polyacetylene nanofibers, PPV nanotubes and MEH-PPV nanowires. Ph.D. thesis, Seoul National University, Seoul. 

FIGURE 1.7 Secondary particles of polyacetylene (a) the powder as synthesized before being dispersed in a polymer matrix at 0.1% (b). (Part (a) is reprinted from Wessling, B., Handbook of Nanostructured Materials and Nanotechnology, vol. 5, ed. H.S. Nalwa, Academic Press, New York, 1999, 525. With permission. Copyright 2000 Elsevier Science Part (b) is reprinted from Wessling, B. and Volk, H, Synth. Met, 15, 183, 1986. With permission. 

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