Nanofabrication of sulfonated polystyrene-g-FEP with silver ion (Ag⁺) using ion beam direct etching and reduction

Functionalized poly(tetrafluoroethylene-co-hexafluoropropylene (FEP)) was fabricated by electron beam (EB) induced grafting technique and chemical sulfonation treatment. The functionalized FEP (s-FEP) films were immersed in the silver nitrate (AgNO₃) solution under ambient condition, to exchange on ionic sites from proton ion-form to Ag⁺ ion-form, and then the Ag-formed s-FEP polymers were obtained. Ag-formed s-FEP was irradiated with 30 keV Ga⁺ focused ion beam (FIB) and 6 MeV/u dispersed Ne¹⁰⁺ ion beam (DIB). The irradiated areas were evaluated by a scanning electron microscopy (SEM) with an energy dispersive X-ray spectroscopy (EDX). In both cases of FIB and DIB irradiations, the nano-scale particles were appeared on the surface of irradiated areas. From the results of EDX analysis for the particles, the peaks which were assigned to silver atoms were clearly detected, and peak intensities were higher than un-irradiated one. It is suggested that the Ag⁺ ions would be reduced by ion beam irradiation and appeared as silver nano-scale particles with pure silver metal and its oxidative chemical compounds.