Salt-free polyelectrolyte behavior of polystyrene-based telechelic ionomers in a polar solvent. 1. Viscosity and low-angle light scattering studies

Some characteristic behavior, typically observed for salt-free polyelectrolytes in water, was observed for the first time for polystyrene (PS)-based telechelic ionomers, which have ionic groups located only at the chain ends, when dissolved in a polar solvent, dimethylformamide (DMF). The characteristic behavior observed by both viscosity and low-angle light scattering measurements for the telechelic ionomers, especially that of the monofunctional ionomer, demonstrates an important role of intermolecular electrostatic interactions in causing the characteristic behavior of telechelic ionomers. The behavior observed in our experiments can best be described by the following picture: each ionomer molecule with a coil conformation, very close to that of polystyrene of the same molecular weight, is separated from yet strongly interacts with other ionomer molecules; and these strong intermolecular electrostatic interactions cause a marked upturn in reduced viscosity and a reduction in scattered intensity