Modification of the Surfaces of Polymer Films Irradiated by Heavy Ions and Nucleopore Nanofilters by XeF_2 Vapors

摘要

The effect of xenon difluoride (XeF_2) vapors on the surface properties of the polymer films irradiated by heavy ions and of the nucleopore nanofilters produced from these films is studied. The procedure for modifying nucleopore membranes made of poly(ethylene terephthalate) and polyimide in XeF_2 vapors is developed. The hydrophilicity, electrosurface properties, and selectivity of modified membranes are investigated. It is shown that the water contact angle on the membrane surface decreases as a result of modification, and the extent of its change depends on the duration and temperature of membrane treatment. Electrokinetic measurements did not reveal any changes in the surface charge during the modification of the membranes prepared from poly(ethylene terephthalate), but their ion selectivity increased twofold. It is shown that the hydrodynamic diameter of the pores of modified membranes reversibly decreases with an increase in transmembrane pressure. The dislosed effects are explained by the presence of an elastoplastic gel-layer on the surfaces of the membraneand its pores. The gel-layer accumulates considerable surface and bulk charges and is characterized by the high hydraulic resistance hindering the convective ion transport.