Fluorescence of perylene- and naphthalene-containing polyimides: Evidence of molecular aggregation and chain coiling in chloroform solution

Fluorescence of several new polyimides in which neighboring imides are linked by a N-N bond was examined in chloroform solutions. For the naphthalene-containing polyimide 1 , analysis of the emission, excitation, and absorption spectra at different concentrations showed the existence of a ground-state intermolecular charge transfer (CT) complex due to chain association and aggregation. For the perylene-containing polyimides 3-6 , the fluorescence was characterized by a low energy band superimposed on the normal perylenediimide bands. This was interpreted as arising from a CT interaction between electron donor-acceptor pairs on the polymers backbone of the same chain, revealing certain degrees of chain coiling of these polymers in solution. © 1995 John Wiley & Sons, Inc.