Has anyone else experienced this?
I made the hydrogel a month ago and kept everything on ice like the protocol suggested. When it was mixed, I stored the hydrogel in the freezer in 50mL falcon tubes. Now when I go to use them, I put the tubes in the fridge to thaw overnight and there is a gel forming on the bottom of the tube. My fridge is at 4oC.
When I used the hydrogel fresh for the first time (never freezer storage), there was no gel until I put it into my 37oC water bath. Polymerization worked perfectly then.