Structure change of PTFE by low‐energy ion irradiation. Restraint of structure collapse by crosslinking structures

The authors irradiated PTFE (polytetrafluoroethylene) with low‐energy nitrogen ions (100 eV) for surface modification. However, PTFE cannot be expected to show improvement in adhesive strength because it is a degradation‐prone polymer and surface fatigue is produced by ion irradiation. We focused on cross‐linked structure to solve this problem. PTFE was changed from a degradation‐prone polymer into a cross‐linked polymer by raising the temperature above the glass‐transition temperature during ion irradiation. As a result, the formation of CF3 bonds was inhibited and degradation was prevented by ion irradiation above the glass‐transition temperature. In addition, combined consideration of the C1s spectrum and the density profile suggests that a cross‐linked structure is effective for improvement of adhesive strength.