A sheet of polyethylene or treated polypropylene can be used to lay the bottom and apply the membrane on top. A coating film of the desired thickness can be obtained by using a coater with a specific coating thickness.
After the membrane is dry, the underlying polyethylene or polypropylene paper can be torn off, and the obtained free test membrane can be cut into the shape required by the permeability cup to be placed in the permeability cup.
If this method cannot be used due to the fragility of the coating film, it can be supplemented with a permeable material as a substrate for testing.
