Role of UV light illumination and DMF soaking in production of PET ion track membranes

The pretreatment effects using UV light illumination and DMF soaking on bulk and track etching rates of PET films were investigated. The wavelength of illuminated UV light plays an important role in sensitizing track etching. Illumination with the light at wavelengths longer than 320 nm showed strong enhancement in the track etching rates without influence on the bulk etching rates, whereas light with the wavelengths lower than 320 nm causes large enhancement in both track and bulk etching rates even in the interior of the material. The track etching rate is found to be not constant along ion tracks, which is attributed to the inhomogeneous distribution of reactive chemical species induced during post-U-V light illumination. Furthermore, the DMF soaking of PET after UV light illumination can enhance the etching sensitivity of the track by more than 100 times. The phenomenon is attributed to the high diffusion of organic solution along tracks after UV light illumination. (C) 2003 Elsevier B.V. All rights reserved.