COMPARATIVE HIGH-RESOLUTION NMR-STUDIES OF N-TYPE AND P-TYPE DOPED POLYACETYLENE FILMS

High resolution NMR provides unique abilities to study either properti es of the polymer chains or behavior of the doping agent in the conduc ting polymers. Magic angle spinning proton decoupled C-13 NMR was appl ied to n-type sodium doped, (CHNa(y))x (y less-than-or-equal-to 0.3), and p-type iodine doped, [CH(I3)y]x (y less-than-or-equal-to 0.19), po lyacetylene films prepared by Shirakawa's method. Also 2-dimensional n utation spectra of half-integer spin (I = 3/2) quadrupolar Na-23 nucle i were measured. All the spectra were studied as a function of the the dopant content, y, determined by weight uptake after doping. The film s were controlled by measurement of the conductivity which was about 1 0 and 50 OMEGA-1 cm-1 for heavily iodine and sodium doped material, re spectively. We discuss our results on: (i) formation of the extended p olycarbonium ions (charged solitons), (ii) doping induced cis/trans is omerization, (iii) partial compensation of (CHNa)x films by oxygen and moisture, (iv) intersite electron-electron correlations on the polyme r chain, and (v) ordering of the sodium ions and occurrence of at leas t two different crystal phases of the polyacetylene-sodium system.