Structural Studies of Conducting Polymer Solutions and Films: Poly(3-methylthiophene)

Abstract

3-Methylthiophene has been polymerized by AsF5in AsF3solution to illustrate the complexity of the chemical and physical interactions which govern conducting polymer solubility and final film properties. The conducting polymer solutions and the electrically conductive films cast from them have been analyzed via solution- and solid-state NMR and EPR and SEM/EDX techniques. The AsF6” ion that has long been proposed as a dopant counterion has been identified at low dopant levels. Sulfur-centered radicals are observed in solution, and carbon-centered radicals are observed in the corresponding cast films. These carbon-based radicals appear to be uncorrelatable with the conductivity of the cast films. From SEM measurements, the electrical and mechanical properties of the electrically conductive poly(3-methylthiophene) films cast from solution are found to be dependent on the sample morphology. © 1989, American Chemical Society. All rights reserved.