Surface analysis of polyethylene and hexatriacontane by high resolution electron energy loss spectroscopy

Surfaces of polyethylene and n‐hexatriacontane were for the first time studied by high resolution electron energy loss spectroscopy (HREELS). The vibrational band energies and intensities were recorded and compared to transmission infrared data. The attribution of most of the bands to methyl, methylene, and C–C vibrations is straightforward; but some of the bands remain unassigned. The intensities of the methyl associated electron energy losses are greatly enhanced. This confirms the extreme surface sensitivity of the spectroscopy and is consistent with a C–C skeleton preferentially oriented perpendicular to the surface. Measured cross section data vs electron impact energy (E0) show that while a dipolar‐type interaction mechanism is dominating some regions of the cross‐section curve, other resonance scattering may contribute significantly for low and high E0. This cross‐section curve shows also that the polymer surfaces are to be considered as a ‘‘condensed gas,’’ with weak intermolecular interaction, in...

[1]  A. Lucas,et al.  Theory of electron energy loss spectroscopy from surfaces of anisotropic materials , 1984 .

[2]  R. Boistelle,et al.  Cinétique de croissance de la face (110) de la paraffine C36H74 en solution: I. Croissance en mileu pur , 1974 .

[3]  Joseph A. Gardella,et al.  High resolution electron energy loss spectroscopy of fatty acids prepared by langmuir-blodgett techniques on polycrystalline silver , 1985 .

[4]  R. Caudano,et al.  X-ray photoemission study of core-electron relaxation energies and valence-band formation of the linear alkanes. II. Solid-phase measurements , 1977 .

[5]  S. Tong,et al.  Large-angle inelastic electron scattering from adsorbate vibrations: Basic theory , 1980 .

[6]  G. Somorjai,et al.  Surface structures of normal paraffins and cyclohexane monolayers and thin crystals grown on the (111) crystal face of platinum. A low‐energy electron diffraction study , 1977 .

[7]  E. Koch,et al.  QUASI-MOLECULAR ANGLE DEPENDENCE OF PHOTOEMISSION FROM THIN FILMS OF POLYSTYRENE* , 1985 .

[8]  R. Caudano,et al.  Infrared optical constants of insulators determined by high-resolution electron-energy-loss spectroscopy , 1984 .

[9]  A. Lucas,et al.  Fast-electron spectroscopy of collective excitations in solids , 1972 .

[10]  R. G. Snyder,et al.  Vibrational analysis of the n-paraffins—II , 1963 .

[11]  A. Lucas,et al.  Vibrational study of the SiO2/Si interface by high resolution electron energy loss spectroscopy , 1985 .

[12]  M. Ratner,et al.  Vibrational spectroscopy and structure of polymer electrolytes, poly(ethylene oxide) complexes of alkali metal salts , 1981 .

[13]  David L. Allara,et al.  Spontaneously organized molecular assemblies. 2. Quantitative infrared spectroscopic determination of equilibrium structures of solution-adsorbed n-alkanoic acids on an oxidized aluminum surface , 1985 .