Pi-Donor Intercalate Polymers: Synthesis, Charge-Transfer Interactions, and Applications

When low-ionization-potential organic donor molecules D such as tetrathiafulvalene, ferrocene, or triarylpyrazolines are chemically attached to a polymer backbone, a number of interesting and potentially useful phenomena are observed in films of the resulting polymers. For example, chemical oxidation, irradiation, or electrochemical treatment of these materials leads to a series of polymers, poly[D
x
(D
⁺
A
⁻
)
1-x
], where D is the polymer-coupled organic molecule, x is the extent of oxidation, and A
⁻
is the charge-compensating anion. Depending on the nature of the bound donor group, these polymers exhibit two kinds of electronic interactions between donor sites which are of charge-transfer origin. These phenomena are responsible for several important properties of this new class of materials that make them interesting as polymer-modified electrodes, as semiconducting polymers, and a high-resolution electron-beam (or x-ray) resists.