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.

This and this answer mention that one common house-hold form of antiseptic iodine is a povidone iodine solution.

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.

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Source "Skeletal formula of povidone-iodine (PVP-I) — a widely used iodine-containing antiseptic and disinfectant."

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    $\begingroup$ The wikipedia article says the PVP-I complex can be loaded into hydrogels. I have some hydrogel tape that stretches readily and would likely easily take up the PVP-I just by dipping the tape (or soaking it) in the PVP-I solution. I can do a quick proxy test with the tape and food coloring. As for removing the solvent from the PVP-I solution, that would likely destroy the complex because the HI is needed to link the polymer to the iodine molecules. If I see the PVP-I in my local pharmacy, I will pick up a small bottle and try my luck at making a hydrogel polarizer! $\endgroup$
    – Ed V
    Aug 25, 2023 at 0:52
  • $\begingroup$ @EdV wonderful! I haven't a clue what "hydrogel tape" is much less have some lying around, looking forward to news of what happens. $\endgroup$
    – uhoh
    Aug 25, 2023 at 2:50
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    $\begingroup$ Well, a 24 hour soak of the hydrogel tape in blue food coloring (in water) resulted in no uptake of the coloring into the tape. It happens that the PVP-I is available, so I might try it directly. I wonder if the world building SE ever considered a truly bizarre world where most experiments worked, even some on the first try? Nah, far beyond ken! ;-) $\endgroup$
    – Ed V
    Aug 26, 2023 at 14:46


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