In this answer I mention how early polarizing filters (e.g. sunglasses) were made by doping a polymer with iodine atoms and then stretching the film to orient the polymer molecules.
Electrons donated by the iodine could then respond to the electric field of the incident light preferentially in the direction parallel to the molecules.
I don't have a feeling for how long those povidone chains are in over-the-copunter povidone iodine solutions are, but I would like to ask how I might try to remove the solvent, which is in this case just water, and see if I could make a film of the povidone-iodine complex, align or stretch it somehow, and see if the result has any polarizing activity.
If I tried to evaporate some, would the iodine remain attached to the povidone chains, or evaporate as well?
An alternative that would align the molecules in a solution somehow would also be interesting.
Source "Skeletal formula of povidone-iodine (PVP-I) — a widely used iodine-containing antiseptic and disinfectant."