[en] This paper shows the experimental outcomes of a study of crystallinity dependent diffraction effects on both elastically-scattered and Auger electrons produced from highly-oriented pyrolytic graphite (HOPG) using a commercial scanning Auger electron microscope (SAM). This system is equipped with a coaxial cylindrical mirror analyser (CMA). Scanning electron images (SEM), backscattered electron images (BSE), Auger maps and the Auger spectra, using a range of relatively low incident electron energies, are obtained and analysed in detail. It is shown that the regional contrast shown in the SEM and BSE images and in the Auger maps, in the electron energy range used, is formed predominantly by forward focusing along the close-packed <21-bar1-bar2>-type atomic chains of the graphite lattice. The intensity of the exiting electrons received by the CMA can be interpreted as a convolution of the diffraction of both incident and exiting electrons, e.g. that of the exiting elastically scattered electrons can vary by up to 50% on changing the incident direction of the primary beam and the orientation of the specimen. Increasing the energy of incident beam enhances forward focusing and increases the contribution from diffraction along the secondary close-packed atomic chains, e.g. the <33-bar04>-type atomic chains present. The carbon (KLL) Auger electrons produced are found to behave in a way similar to the primary electrons in regard to the diffraction process but with less marked diffraction evident

[en] Polypropylene film has been modified in an air dielectric barrier discharge using two different electrode-platen configurations: stainless steel wire electrode-rubber platen or ceramic electrode-aluminium platen combinations. Modified films were characterised by static contact angle measurements, X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS) and Fourier transform infrared spectroscopy (ATR-FT-IR). Surface hydrophilic modification appears to be governed by the presence of low-molecular weight oxidised functionalities using XPS and SIMS techniques. Irrespective of the type of electrode-platen combination used to obtain the discharge, oxygenated functionalities of identical nature are formed on the polymer surface. However, the degree of oxidation obtained by the discharge using the wire electrodes with the rubber platen was considerably greater. Further increase in the observed hydrophilicity due to molecular rearrangement and development of stable oxygenated functionalities was evident after 1 month of post-processing analysis