The thin, rubbery material also has promise for other uses, such as tarps, or camping equipment. It is tear resistant, and can be patched with more silicone.
Although translucent, I find the curtain visually opaque enough for privacy. Over the years, algae will grow over it, as it does on the walls, which will further increase opacity and make the curtain blend in more with nature. If one wanted to get fancy with designs, one could "paint" on it with colored silicone rubber, but I like it just the way it is.
Step 1: Making the Material
If I had a factory to make this material, I would probably try to find a rigid and smooth floor surface to work on that the silicone wouldn't stick to. That would avoid the wrinkles and bottom side defects and make saturation a one-step procedure.
It is easy to apply the silicone rubber. Just squeeze some out on the mat material and spread it around with the palette knife. Press down firmly. The final thickness of the saturated material is basically the same as that of the raw material.