(A) new class of ionic polyacetylene

Abstract

A new type of conjugated ionic polyacetylene was synthesized by metathesis polymerization of betaine monomers, alkyl dipropargyl (4-sulfobutyl) ammonium betaines(ADPSAB). The polymerization of ADPSAB was carried out with various transition metal catalyst systems. The $MoCl_5$ and $PdCl_2$ were found to be a particularly effective catalyst for the cyclopolymerization of the betaine monomers. FT-IR, $^1$H NMR, $^{13}$C NMR and UV-visible spectroscopies showed that poly(ADPSAB) possess polyene structure having cyclic recurring units in the polymer backbone. Unlike polyelectrolyte, the resulting polymers were more soluble and showed higher viscosities in the salt than in salt-free solution (antipolyelectrolytes). When doped with an accepter such as iodine, the polymers exhibited a substantial increase($\sim10^3$S/cm) in electrical conductivity compared to the undoped state($-10^{-10}$S/cm).