Oriented Thin Films of Insoluble Polythiophene Prepared by the Friction Transfer Technique

A thin film of unsubstituted polythiophene (PT), an insoluble conjugated polymer, with molecular chains uniaxially oriented in plane was prepared by the friction transfer method. The structure of highly oriented thin films of PT was investigated using grazing-incidence X-ray diffraction (GIXD), ultraviolet-visible (UV-vis) spectroscopy, and infrared (IR) spectroscopy. The polarized UV-vis and IR spectra and GIXD measurements showed the PT molecular chains were well aligned in parallel to the friction direction. The GIXD studies clarified that the polymer backbones were aligned with very narrow distribution, such that the half-width was about 4 degrees. The degree of orientation of the PT friction-transferred film was higher compared with those of regioregular poly(3-alkylthiophene)s. Moreover, the GIXD results show a preferred orientation where the a-axis is perpendicular to the substrate plane.

Automated summary

The study investigated the structure of a thin film of unsubstituted polythiophene prepared by the friction transfer method, showing highly oriented molecular chains in the plane with a high degree of alignment. The polymer backbones were aligned parallel to the friction direction with a narrow distribution, leading to a higher orientation compared to regioregular poly(3-alkylthiophene)s. Additionally, the GIXD results indicated a preferred orientation where the a-axis is perpendicular to the substrate plane.