Recent studies of insulating polymers with high-resolution electron energy loss spectroscopy

The application of high-resolution electron energy loss spectroscopy (HREELS) to the study of insulating polymer surfaces is reviewed. Such studies require the use of a secondary electron beam to prevent charging and to achieve stable surface potentials. Industrial grade polymers, obtained as thin sheets or cut from rod stock, are also rough and disordered compared to the single-crystal or thin film surfaces normally studied by HREELS. Therefore, the practical application of HREELS to insulating polymer samples has been limited by resolution, intensity and stability under secondary electron beam neutralization. This paper reviews recent progress of a method which combines modem instrumentation, low-energy secondary electron beam neutralization and spectral restoration algorithms. It is demonstrated that this method approaches a practical resolution criterion of 5 meV (40 cm(-1)) at relatively high spectral intensities as shown for polystyrene and polytetrafluoroethylene. The application of HREELS to surfaces modified by low-pressure plasma treatment is also illustrated. (C) 2001 Elsevier Science B.V. All rights reserved.