X-ray photoelectron spectroscopic studies of ionic interactions in poly(styrenesulfonic acid)/poly(vinylpyridine) complexes

Abstract

X-ray photoelectron spectroscopic (XPS) measurements were made on complexes obtained from poly(styrenesulfonic acid) (PSSA) and poly(4-vinylpyridine) (P4VPy) or poly(2-vinylpyridine) (P2VPy). Ionic interactions in the complexes are evidenced by the development of a high-binding energy component of the N1s spectra. The extent of protonation of pyridine groups, ranging from 34 to 86%, is a linear function of the surface composition of the complex. As compared to the poly(vinylphosphonic acid) (PVPA)/poly(vinylpyridine) complexes, protonation is more extensive in the PSSA/poly(vinylpyridine) complexes. The position of the nitrogen in the pyridine ring does not have a significant effect on the extent of protonation. Fourier-transform infrared (FTIR) spectroscopy also showed the existence of ionic interactions in the various complexes. © 1998 Elsevier Science B.V.