Characteristics of polycarbonate and polyester nuclear track membranes

Abstract Background: Polycarbonate (PC) and polyethylene terephthalate (PET) films were widely used as the materials for nuclear track membranes because both of them could be etched effectively with alkaline solutions. Purpose: This paper aims to research the characteristics of polycarbonate and polyester nuclear track membranes. Methods: The PC and PET foils were irradiated with Au ions (11.4 MeV·u^-1) and Kr ions (20 MeV·u^-1) respectively. Then the irradiated foils were etched with the NaOH aqueous solution. The pore sizes of PC and PET nuclear track membranes were in the range of 20 nm to 400 nm and 100 nm to 700 nm, respectively. Results: The pore sizes and their distributions of these membranes were characterized with scanning electron microscopy (SEM) and the method of gas-liquid displacement, respectively. It suggested that the irradiation fluence determined the membrane pore density; the longer the etching time, the larger the membrane pore size, and the evener the distribution of membrane pore sizes. The surfaces of the irradiated PET membranes were more hydrophilic than those of the irradiated PC membranes. Conclusion: The experimental results suggest that bovine serum albumin (BSA) in aqueous solution could be rejected effectively by PET nuclear track membranes with different membrane pore sizes at 0.15 MPa and ambient temperature. The smaller the membrane pore size, the higher the rejection to BSA, and the higher the operating pressure required, resulting in more serious membrane fouling. (authors)