In the well established aggregation model, a one-dimensional linear polyiodide [I.sub.3.sup.-] or [I.sub.5.sup.-]) is surrounded by parallel-oriented PVA amorphous chains [17, 18].
Such coloring on cooling indicates the formation of PVA-iodine complexes in which the iodine has formed polyiodide ions through its interaction with PVA [19, 28].
Subsequently, iodide ion may take up more iodine molecules to form polyiodide ([I.sub.3.sup.-], [I.sub.5.sup.-]) ions [11-13].
In the presence of solvent, iodine changes to ionic form, [I.sup.-], that may form complex with more iodine molecules to form polyiodide ions like [I.sub.3.sup.-], [I.sub.5.sup.-] etc.
The doping of iodine into iodide matrix formed polyiodide
Kloo, "Molten and solid trialkylsulfonium iodides and their polyiodides
as electrolytes in dye-sensitized nanocrystalline solar cells," Journal of Physical Chemistry B, vol.