Acid photogeneration from sulfonium salts in solid polymer matrices

The major photoproduct from irradiation of triphenylsulfonium salts is a Bronsted acid. This photochemical process has been used in several polymer film applications where the acid is used for crosslinking of films or other acid catalyzed reactions. Despite the widespread application of these materials, very little is known about the efficiency of acid generation in polymer films or the extent of the catalytic chain. This paper describes the use of a merocyanine dye technique to analyze for acid production in polymer films. The amount of acid produced on irradiation can be determined by this method and the extent of the catalytic chain then be determined.