The photopolymerization of styrenesulfonate initiated by dyes

Styrenesulfonate was photopolymerized in the presence of the anionic dye Eosine Y. The study of the reactions of the excited- and ground states of the species involved in the photoinitiation process showed that the monomer aggregates forming hydrotropic domains in aqueous solution at concentrations above 0.1 M. Although the dye is distributed between these domains and the bulk of the solution, the main initiating pathway involves excited dyes outside the clusters. These results are opposite to those obtained using the cationic dye Safranine, which starts photopolymerization from the dye molecules incorporated in the monomer clusters.