Synthesis, characterization and electrical properties of new conducting poly(1-alkyl-3,4-dimethyl-2,5-pyrrolylene)

摘要

An interesting feature of the pyrrole system is the ability to readily prepare a number of functionalized polymers by polymerization of pyrrole monomer. In particular, an electrochemically prepared polypyrrole shows high conductivity (>100 Scm~(-1)), relative stability to air and moisture in its oxidized form, ability to form strong coherent films, and ease of synthesis. Properties also have been modified by polymerizing pyrrole derivatives with 1-methyl-3,4-dimethoxy and 3,4-dimethoxy substituents. Conductivities of these polymers are 10~(-2) Scm~(-1) and 6 Scm~(-1), respectively. However, the room temperature conductivities of poly(1-alkyl-2,5-pyrrolylene)(alkyl = methyl, hexyl, dodecyl) prepared by chemical oxidation fall in the range 10~(-3) to 10~(-6) sCM~(-1). Recently, we reported the difference in conductivity between poly(1-hexyl-2,5-pyrrolylene)(σ = 1.2 * 10~(-6) Scm~(-1)(7) and poly(1-hexyl-2,5-pyrrylene vinylene)(σ = 2.5 Scm~(-1))(8) suggesting that the low conductivities of 1-alkylsubstituted polypyrroles as prepared by oxidative polymerization arise from steric interactions between adjacent rings.