Structure Formation in Conducting Polymers

Abstract

The properties of polymer materials are strongly dependent on their final structure and morphology. A control of nucleation from a homogenous solution or solid phase is one of the key factors in the determination of the final structure. The second essential stage is the systematic control of the growth process during the order formation. In electrically conducting polymers, the property (conductivity) is similarly affected by the structure and morphology. We have investigated the phase separation processes of poly(3-dodecylthiophene) (PDDT) from a homogeneous melt state. An order-disorder transition (ODT) was observed during a slow cooling process. Schlieren textures were developed as shear stress was applied. In PDDT-blends, the phase separation was followed in-situ with light scattering experiments and the early stages of the phase separation were defined as the linear protion in spinodal decompositon. This formation of bicontinuous pathways was confirmed with conductivity measurements. The homogeneity of polyaniline solutions was studied by thermal analysis and it was shown that m-cresol associates strongest with doped complex. This synergism supports the good solvent concept for m-cresol. Further on, the aggregation was followed by CD-spectroscopy as the used dopant was chiral. All the above results offer reasonable hope for a kinetic control of the order formation in conducting polymers.