Photo-irradiation effects on poly(vinylpyridines)

Luminescence and surface morphology changes of poly(2-vinylpyridine) and poly(4-vinylpyridine) thin films were determined with UV-irradiation (∼254 nm). Both polymers colored in yellow with the UV-irradiation, and their 2D-emission spectra indicated that new emission bands appeared at longer wavelengths in visible region. On the other hand, only poly(2-vinylpyridine) has significant changes in its surface morphology, while poly(4-vinylpyridine) has hardly any changes using AFM observation. The difference in the morphological behaviors should be originated from the difference of the nature of their photo-excited states.