Electronic structure and molecular orientation at thin film surfaces of pendant-group polymers studied by outermost surface spectroscopy using metastable atoms

Metastable-atom electron spectroscopy (MAES) and ultraviolet photoelectron spectroscopy (LTS) were used to study the outermost surface of thin films o f pendant group polymers: polystyrene, poly(2-vinylnaphthalene), and poly(9 -vinylcarbazole). MAES is selectively sensitive to the outermost surface, a nd indicated that the surfaces of the polymer films were very clean, even t hough they were prepared by spin-casting in a room atmosphere. By compariso n with gas-phase spectra and molecular orbital calculations of model molecu les with pendant groups, it was confirmed that the principal constituent at the outermost surface of these polymer films is the pendant groups. Furthe rmore, it was observed that the intensity for sigma (C-H) states of the pen dant group is stronger in MAES spectra than in UPS spectra, indicating many pendant groups are inclined at large tilt angles. (C) 2001 Elsevier Scienc e B.V. All rights reserved.