Diiodobutadiyne forms cocrystals with bis(pyridyl)oxalamides in which the diyne alignment is near the ideal parameters for topochemical polymerization to the ordered conjugated polymer, poly(diiododiacetylene) (PIDA). Nonetheless, previous efforts to induce polymerization in these samples via heat or irradiation were unsuccessful. We report here the successful ordered polymerization of diiodobutadiyne in these cocrystals, by subjecting them to high external pressure (0.3-10 GPa). At the lower end of the pressure range, the samples contain primarily monomer, as demonstrated by X-ray diffraction studies, but some polymerization does occur, leading to a pronounced color change from colorless to blue and to the development of intense Raman peaks at 962, 1394, and 2055 cm-1, corresponding to the poly(diacetylene). At higher pressures, the samples turn black and contain primarily polymer, as determined by solid-state NMR and Raman spectroscopy. Both density functional theory calculations (B3LYP/LanL2DZ) and comparisons to authentic samples of PIDA have confirmed the data analysis.

Electrospinning is a relatively simple and versatile method to produce polymer nanofibres and their composites. In this work, functionalized multiwalled carbon nanotubes (f-MWNTs) were used for the fabrication of conducting nanocomposite fibres, in comparison with the composite nanofibres made of unfunctionalized MWNTs (u-MWNTs). Our results showed that the addition of f-MWNTs could improve the dispersion of carbon nanotubes in the polymer solution and therefore result in composite nanofibres with uniform diameters by electrospinning. Alignment of the composite nanofibres was achieved by using a rotating drum as the collector. F-MWNTs were found to align parallel to the axis direction of the nanofibres. DC electrical properties of a single composite fibre were investigated at room temperature as well as cryogenic states (100–300 K). An electrical percolation phenomenon was observed for nanofibres with different mass fractions of MWNTs. It was shown that the conductivity of the material could be significantly improved above the percolation threshold. The conductivity could be of several orders of magnitude higher than the pure PVAc.

The prospect of using phonons in amorphous silicon to convey information from one location to another is investigated. It is known that the phonon lifetime in amorphous silicon is anomalously long and the phonon diffusivity is relatively large as compared to crystal silicon and other materials. A commercial Raman spectrometer measuring from the film side operating at 785 nm was used in conjuncture with a 470 nm bias light illuminating the glass side of amorphous silicon films deposited onto glass substrates. All measurements were conducted at liquid nitrogen temperature. Analysis indicates a phonon diffusion length of a least 0.5 µm. These results directly lead to tantalizing prospects for phonon engineered amorphous silicon technology.

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