STUDY OF THE EFFECT OF ACID DOPING ON THE PROPERTIES OF POLY(N-SELENO-P-PHENYLENE DIAMINE)

Poly(N-seleno-p-phenylene diamine), before and after doping, has been studied by infrared absorption, X-ray electron spectroscopy (XPS), ele ctron spin resonance (ESR) and room temperature conductivity measureme nts. The dopants used were inorganic (HCl, H2SO4) and organic (CF3COOH , CH3SO3H, CH3OOH) acids. It is shown by IR absorption that only the C H3COOH doping does not systematically destroy the C-N and/or the N-Se- N bonds. The XPS analysis shows that some oxygen is present in the pol ymer even before doping. This oxidation and the dissymmetry of the mon omer can justify the presence of an ESR signal before doping. After do ping with CH3COOH the increase in the ESR signal and can be attributed to polymer protonation. This is in good agreement with the new compon ent of the N1s signal obtained by XPS which can be attributed to N+ ra dicals. However, it is shown by XPS that when the CH3COOH concentratio n increases, the N-Se-N bonds are partly destroyed which can explain t he decrease in the ESR signal and the conductivity. (C) 1997 Elsevier Science Limited.