A mechanistic study of the photocrosslinking of poly(vinyl alcohol) films modified with pendant styryl pyridinium groups

✍ Scribed by Eleanor S. Cockburn; R. Stephen Davidson; Susan A. Wilkinson; John Hamilton

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 176 KB
• Volume: 24
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(88)90188-7

✦ Synopsis

Films of poly(vlnyl alcohol) carrying pendant styrylpyridinium groups exhibit fluorescence typical of the excimer of the pendant group. Irradiation of the films leads to elimination of the excimer emission band. Following the photoreaction by IR diffuse reflectance spectroscopy shows that there are unreactive c~omophores which are presumably isolated styrylpyridinium groups or aggregates which cannot lead to photodimerisation. The photoreaction is so rapid that it was impossible to measure the fluorescence lifetimes of the chromophore using an argon ion laser as light source. The results show that in thin films there is considerable aggregation of the styrylpyridinium groups, accounting for the rapid photoreaction which presumably occurs via an excimeric intermediate.