CHARACTERIZATION OF UNDOPED POLY(3-OCTYL THIOPHENE)

Many derivatives of electrically conducting polythiophenes are soluble and fusible in their undoped state. Poly(3-alkylthiophenes) are, howe ver, not always 100 percent soluble in organic solvents such as chloro form, THF and anisole. The solubility decreases as a function of time. The insoluble portion of the polymer forms a gel which swells in diff erent solvents. We have studied the differences between the soluble an d insoluble parts of poly(3-octyl thiophene) and the effect of differe nt solvents and hot pressing on the structure (crystallinity) of the p olymer using X-ray diffraction and to some extent solid state NMR and ESCA. Indications for piezoelectric effect in poly(3-octylthiophene) a re discussed briefly.