Short-time plasma pre-treatment of polytetrafluoroethylene for improved adhesion

Fluoropolymers with their unique properties (chemical inertness, thermal st ability, low surface tension, mechanical stability) are used in many indust rial applications. One disadvantage of these fluoropolymers is their poor a dhesion to other materials. In this work a short-time plasma pre-treatment of polytetrafluoroethylene (PTFE) with a low pressure microwave plasma was investigated. The Plasmodul (R) source allows the pre-treatment of PTFE sub strates with an ammonia plasma (NH3). The newly developed plasma source Pla nartron (R), which is derived from the Duo-Plasmaline (R), was used for imp roving the adhesion properties of PTFE by generating oxygen and nitrogen pl asmas. PTFE foils were modified on both sides by plasma treatment for typic ally 30 s. After bonding the foils to aluminum dollies using a 2-K-epoxy re sin the bonding strength of the adhesive joint was measured directly by pul l off tests. Some modified foils were additionally investigated by Fourier- transform infrared spectroscopy. (C) 2001 Elsevier Science B.V. All rights reserved.