Rubbing treatment before chemical surface modification enhances deep trapping of positive charge on polytetrafluoroethylene (PTFE) electrets

In order to achieve significant improvements of their electret stability, we have developed a two-stage procedure for the surface modification of PTFE films. In the first stage, the reactivity of the polymer surface is increased by means of rubbing with a dielectric counter-body. In the second stage, titanium-containing nanostructures are formed by treating the tribo-activated polymer-film surface with titanium-tetrachloride (TiCl4) vapor. The samples are then comprehensively studied by means of X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and thermally stimulated surface potential decay (TSPD).