Conductivity in dialkylsulphide—iodine mixtures

Ionic conductivity, infrared and Raman spectroscopic studies of 1-methyl-3-propylimidazolium iodide ionic liquid with added iodine

“…This phenomenon seems to appear only in ionic liquid electrolytes, whereas in molecular liquid electrolytes the saturation of conductivity at high concentrations of mobile species is usually observed. The increase of conductivity also ruled out the existence of iodine -its absence was independently deduced from the Raman spectra -which is not conducting specie in solutions and would inevitably lead to a drop in the conductivity values, as already mentioned by Stegemann et al [18]. The results were fully consistent with the basic Grotthus mechanism where continuous paths of mobile carriers within the material are needed for conduction to be possible.…”

“…One of the specific properties encountered in condensed ILs is the finding that the addition of gelators [17] or accomplishment of condensation via the formation of siloxane bonds [14,15] affects the ionic conductivity, but contrary to expectation, this increases on the addition of iodine, despite the fact that dissolved iodine is not a conducting specie [18]. Namely, the presence of iodine leads to the formation of various polyiodides [19,20], i.e.…”

“…The existence of polyiodides has been successfully proven for Et 3 SI x (Et = ethyl, x = 3 and 5) [18] using liquid X-ray scattering and Raman spectroscopy [23]. It was shown that the structure of Et 3 SI x could be described by iodide or tri-and pentaiodide ions solvated by iodine units.…”

“…The interactions between the iodine and iodide species yield the delocalisation of charge over the polyiodide formed [18] and in the presence of outer electrical field leads to asymmetric charge distribution and bond reorientation. An additional exchange-reaction-based diffusion (D ex ) conduction process, which originates from electron exchange between the redox couple, accompanies physical diffusion (D phys ) [21].…”

Characterization and Conductivities of Polyphosphazene-Iodine Complexes

“…6 However, a number of monomers and non-conjugated polymers also form stable, highly conductive complexes with iodine. Examples include poly(vinylpyridine) 7 and poly(alkylsulfides), 8 The mode of conduction in iodine-doped poly(isoprene) has also been examined by several groups. 9 " 11 The poly(organophosphazene) [NP(OCH 2 CH 2 OCH 2 CH 2 OCH 3 ) 2 ] n (MEEP) was first synthesized and studied in our laboratories as a solid solvent for Li or Ag triflate salts.…”