Alternating copolymers containing an aromatic chromophore in every monomer unit 1.: Fluorescence properties of poly(benzyl methacrylate-alt-styrene)

Alternating copolymer of benzyl methacrylate and styrene (a-BzSt) was synthesized and its fluorescence properties were compared with those for alternating copolymer of methyl methacrylate and styrene (a-MSt) and the corresponding random copolymers. Both a-BzSt and a-MSt exhibited a predominant monomer emission which decayed exponentially, indicating no excimer formation in these polymers. However, the styrene and methacrylate monomer units in a-BzSt were found not to have exactly the same chromophores because differences in the fluorescence intensity and lifetime were observed. The fluorescence quenching studies showed that there was no noticeable increase in the quenching efficiency for a-BzSt and a-MSt compared with that for the corresponding random copolymers. Therefore, energy migration contributes inefficiently to the quenching in these alternating copolymers. This may be due in part to an intrinsically low migration efficiency of phenyl chromophores.