You can produce transparent polymeric membrane by casting  of soluble polymer in a petri dish or  surface of glass such PVA  in water and cellulose acetate in acetne

Actually I've only worked with PVA. It occurs to me that perhaps using a compatibilizer, or working at very low concentrations of one of the polymers may achieve transparency. Important, if the mechanical and permeation of gases and water vapor, which is transparent or nontransparent is not decisive in the packaging properties are preserved.

PSf transparent membrane can be prepared by TIPS method. Usualy PVA membrane is also transparent through TIPS method. For cellulose acetate you have to apply vacuum for casted  membrane  on glass plate and acetone solvent.

 Dear Dr.Ali,  I had an experience in casting the membrane using cellulose acetate, polysulfone and polyurethane as individual or blended castings together.  Here the casting mechanism is involved by phase transfer which is comes from organic solvent to aqueous phase(precipitation method). Hence it is enriched with opaque not transparent membrane. However if you adopt different method certainly you can get transparent membrane. I too have experience in polystyrene membrane using organic solvent and then left for evaporation after casting, the resultant membrane is  transparent which is used for gas sorption studies.