High‐resolution electron energy loss spectroscopy and infrared spectroscopy of polymer surfaces: High‐resolution and orientation effects of polytetrafluoroethylene films

The vibrational structure of oriented polytetrafluoroethylene has been studied using high‐resolution electron energy loss spectroscopy (HREELS) and infrared spectroscopy. Record‐high resolutions of 6–15 cm−1 in HREELS with a state‐of‐the‐art spectrometer are reported. Selection rules and orientation effects probed by the two different spectroscopies are discussed and comparisons are made between surface and bulk structure. Resonance electron scattering in HREELS has been used to study orientation effects of an intense Raman‐active ν(C–C) mode at 730 cm−1. The resonance seen in HREELS is identified as the σ*(C–C) state. HREELS results have been related to near‐edge x‐ray absorption fine structure results. We discuss several future improvements that need to be addressed if ultrahigh resolution EELS is to become a more applicable and powerful tool for the study of polymer surfaces.