Synthesis and investigation of new water soluble sulfonated rigid‐rod polynaphthoyleneimide

Abstract A new water‐soluble rigid‐rod sulfonated polynaphthoyleneimide (PNIS) was synthesized. The structure of PNIS has been confirmed by elemental analysis, NMR ( 1 H, 13 C), full X‐ray investigation of model compound. Viscosity measurements, sedimentation and light‐scattering experiments of PNIS solutions confirm the suggested aggregation of this polymer and an increase of its molecular weight without being substantially changed in different types of aqueous solution. These aggregates could consist of very tightly packed rigid rods.