Halato-telechelic polymers. IV - Synthesis and dilute-solution behavior

Halato-telechelic polymers (HTP) result from the complete ionization of both ends of telechelic prepolymers. Their behavior in nonpolar solvents is characterized by a very abrupt increase of viscosity at increasing concentration, so that gel formation is noted at concentrations as low as 1.5 gdL-'. The nature of the ion pairs, polarity of the medium, and temperature influence significantly the gel formation and prove its electrostatic origin. The depressive effect of any polar additive on the gelation requires drastic conditions in the synthesis of reproducible materials. In this respect, an efficient synthetic pathway has been proposed. The influence of molecular weight and end-to-end distance of the prepolymer shows the determinant role played by the polymeric backbone on the ion aggregation process