[Polly Murs]

I'm using NIPAAm/AAm to make gels
APS/TEMED redox system

the resulting gels are opaque... what is causing this?

I placed them in boiling water to bring them above their lcst.
they shrank as expected, but when I placed them in room temp water, they instantly started to rehydrate and are now translucent!

can someone offer a possible explanation of what is going on?

thanks

[pgk]

Probably you mean “Hydrogels of poly(N-isopropylacrylamide)/acrylamide copolymer that are polymerized via ammonium persulfate and tetramethylethylenediamine initiation”.
Anyway, take a look to the following links that might be helpful (If you haven’t seen them, already)?
http://www.falw.vu/~microb/Protocols/Manuals/Acrylamide_polymerization.pdf
https://labpolimeros.eng.ufmg.br/wp-content/uploads/2014/08/Structural_Charact_of_PNiPAAm_Gels_and_Some_of_their_Copol_with_Acrylamide_Through_PALS.pdf
Question 1: What was the ratio of “AAm per NIPAAm”?
Question 2: Was the water that you used, “ultra-pure” and completely free of ions and salts?
Question 3: Has the polymerization been occurred under an inert atmosphere?
Question 4: Was the “freezing” instant or gradual?