High resolution NMR provides unique abilities to study either properties of the polymer chains or behavior of the doping agent in the conducting polymers. Magic angle spinning proton decoupled 13C NMR was applied to n-type sodium doped, (CHNay)x (y ≤ 0.3), and p-type iodine doped, [CH(I3)y]x (y ≤ 0.19), polyacetylene films prepared by Shirakawa's method. Also 2-dimensional nutation spectra of half-integer spin (I = 3 2) quadrupolar 23Na nuclei were measured. All the spectra were studied as a function of the dopant content, y, determined by weight uptake after doping. The films were controlled by measurement of the conductivity which was about 10 and 50 Ω-1cm-1 for heavily iodine and sodium doped material, respectively. We discuss our results on: (i) formation of the extended polycarbonium ions (charged solitons), (ii) doping induced cis/trans isomerization, (iii) partial compensation of (CHNa)x films by oxygen and moisture, (iv) intersite electron-electron correlations on the polymer chain, and (v) ordering of the sodium ions and occurrence of at least two different crystal phases of the polyacetylene-sodium system.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Materials Chemistry
- Polymers and Plastics