The surface composition of uncoated and coated polymer foils was compared through using a TFA XPS instrument (Physical Electronics Inc., Chanhassen, MN, USA). The ultimate pressure in the XPS vacuum chamber was ~6 × 10−8 Pa. The samples were irradiated with X-rays from monochromatic Al Kα1,2 radiation at 1486.6 eV. The diameter of the analysis area was 400 µm.
The photoelectrons were detected with a hemispherical analyzer located at a take-off angle of 45° with respect to the normal sample surface. Survey-scan spectra were acquired at a pass energy of 187.85 eV, while, for C 1s, individual high-resolution spectra were taken at a pass energy of 29.35 eV with a 0.125-eV energy step. An additional electron gun was used for charge neutralization. All spectra were referenced to the main C 1s peak of the carbon atoms, which was assigned a value of 284.8 eV. The spectra were analyzed using MultiPak v8.1c software (Ulvac-Phi Inc., Kanagawa, Japan, 2006) from Physical Electronics, which was supplied with the spectrometer.
The photoelectrons were detected with a hemispherical analyzer located at a take-off angle of 45° with respect to the normal sample surface. Survey-scan spectra were acquired at a pass energy of 187.85 eV, while, for C 1s, individual high-resolution spectra were taken at a pass energy of 29.35 eV with a 0.125-eV energy step. An additional electron gun was used for charge neutralization. All spectra were referenced to the main C 1s peak of the carbon atoms, which was assigned a value of 284.8 eV. The spectra were analyzed using MultiPak v8.1c software (Ulvac-Phi Inc., Kanagawa, Japan, 2006) from Physical Electronics, which was supplied with the spectrometer.