Alignment of semiconducting liquid crystalline polymers induced by hot stylus rubbing

• Published in: Japanese Journal of Applied Physics Vol. 63; no. 3; pp. 31001 - 31008
• Main Authors: Honma, Michinori, Otsuka, Takuya, Ito, Ryota, Pau, Stanley, Nose, Toshiaki
• Format: Journal Article
• Language: English
• Published: Tokyo IOP Publishing 01.03.2024; Japanese Journal of Applied Physics
• Subjects: Birefringence; Diffraction efficiency; Gratings (spectra); liquid crystal; Liquid crystal polymers; Liquid crystals; microrubbing; molecular orientation; Molecular structure; Orientation; polyfluorene; Rubbing; Shear forces; Spin coating; Styli; Thin films; Vertical loads
• ISSN: 0021-4922; 1347-4065
• DOI: 10.35848/1347-4065/ad272b

Abstract We introduce a microrubbing process using a small hot stylus to create a liquid crystalline (LC) polymer possessing a microscale thread-like structure with good molecular orientation properties. In this process, the spin-coated thin film was rubbed using a hot stylus to apply a lateral shear force to the film and induce the LC phase. The effects of the rubbed line thickness (or created orientation thread spacing) on the processing temperature and vertical load were studied to construct a formation model of the orientation threads. Furthermore, a regular arrangement of the orientation threads, which can function as a diffraction grating, was fabricated to estimate the induced birefringence of the threads based on analyzing the polarization dependence of the diffraction efficiency. It was found that the induced birefringence could be considerably high, ensuring that a high orientational order is induced by the hot stylus rubbing procedure.