Magnetism in Pristine Pi-conjugated Polymers

In this study, the magnetic and magneto-optic properties of -conjugated polymers were investigated. This research was initiated by the observation of extremely strong Faraday rotation in films of pristine highly regioregular poly3-alkylthiophenes and subsequently a ferromagnetic hysteretic behavior at low temperature 20K in these polymers. Concomitantly nanoscopic doughnut structures diameter 12 nm were observed in such thin films spin coated from a poor solvent toluene. Interestingly all such properties and structures were absent from regiorandom poly3-alkylthiophenes. Over the course of the project, we developed an extended portfolio of polythiophenes, achiral as well as chiral, which have been thoroughly characterized in their chemical properties. Faraday measurements on these polymers, in solution and thin films, have clearly shown the great potential of these polymers as materials for magneto-optical applications. The results of this project have also opened a new way to organic magnetism of environmental stable polymers, while on a more theoretical way the study of persistent currents in organic cyclic structures has been initiated.