Modification of the Surface Layers of Fluoropolymer Films by DC Discharge for the Purpose of the Improvement of Adhesion Properties

Abstract

The effect of dc discharge treatment at the anode and cathode on the surface properties of polytetrafluoroethylene (PTFE), tetrafluoroethylene–hexafluoropropylene copolymer (FEP) and poly(vinylidene fluoride) (PVDF) polymer films was studied. It was found that the modification of the films under conditions that ensure the separation of the discharge active species acting on the polymer materials makes it possible to achieve substantially lover values for the contact angle and higher values for the surface energy than in the case of other modes of discharge. The changes in the composition and structure of the films were studied by means of IR spectroscopy and electron spectroscopy for chemical analysis (ESCA). It was found that new oxygen-containing groups are formed on the polymer surface as a result of dc discharge treatment. To appreciate the adhesion characteristics of fluoropolymer films modified by dc discharge, American Society for Testing and Materials Standard Test Method for Measuring Adhesion by Tape Test (ASTM D3359-02) was used. The adhesion tape Scotch 810 and vacuum metallization of the film surface are account for the basis of this method. It was found that the adhesive bonding strength of the plasma treated films substantially increased.