The photophysics of poly(p-pyridine) polymethylmethacrylate blends

We have co-dissolved poly(p-pyridine) (PPY) and polymethylmethacrylate in formic acid and cast films from these blends. We observe on increasing dilution that PPY absorption and emission changes from that characteristic of its solid state to that predominantly of its solution state. This is ascribed to increasing inter-ring torsion angle as PPY-PPY inter-chain interactions are diluted.