After hydration, 1.5 g portions of the solutions were rolled onto a
plastic covered, stainless steel board by using a stainless steel roller
with a recess of 0.34 mm in order to achieve consistent film thickness.
The roller with the film on it was then placed in a 5wt.% calcium
chloride bath for 60 s in order to gel the film. After 60 s, the film was
fully cross-linked on both sides and could be peeled off of the roller.
The cross-linked film was put into a folded piece of plastic wrap to
prevent drying of the film before it was tested.