Electrochemical, Magnetic, and Electrical Properties of α,ω-Capped Sexithiophene Films. Part 3. Conduction in Poly(bis-terthienyl-B)s (B = Ethane, Disulfide, Diacetylene, Acetylene, Ethylene)

TLDR: In this article, the same authors showed that conduction proceeds without the help of the links via a direct redox hopping between sexithiophene blocks of adjacent polymer chains, and that the polymers obtained are characterized by cyclic voltammetry, EQCM, UV−vis, and FTIR spectroscopy, in situ ESR and in situ conductivity.

Abstract: Electrochemical oxidation of bis-terthienyl-B (B = ethane, disulfide, diacetylene, acetylene, ethylene) has been investigated. Monomers without and with 3,3′′-dialkylsubstitution are regularly coupled to polymers alternating sexithiophene and B moieties. The corresponding terthienyl homopolymers have also been produced for comparison. The polymers obtained are characterized by cyclic voltammetry, EQCM, UV−vis, and FTIR spectroscopy, in situ ESR and in situ conductivity. The conductivities of p-doped polymers with ethane or disulfide bridges fall in a narrow range (1−5 × 10−2 S cm−1) and are practically the same as those of α,ω-dimethylsexithiophene (1 × 10−2 S cm−1), suggesting that conduction proceeds without the help of the links via a direct redox hopping between sexithiophene blocks of adjacent polymer chains. In the cases of diacetylene and acetylene, conduction changes from redox to bipolaron-type but only in the case of ethylene the conductivity jumps to high values (1−5 S cm−1) corresponding to th...