著者

宇佐美 清章 坂本 謙二 荒谷 毅 潮田 資勝

出版者

一般社団法人 日本液晶学会

雑誌

日本液晶学会討論会講演予稿集 (ISSN:18803490)

巻号頁・発行日

vol.1999, pp.6-7, 1999

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We have measured the polarized infrared (IR) absorption spectra of poly[4,4'-oxydiphenylen-l,2,3,4- cyclobutanetetracarboxyimide] (CBDA-ODA) films irradiated with linearly polarized ultraviolet light (LPUVL) of wavelength 〜 250 nm. The measurement was carried out for a very thin film (10 nm thick) as a function of the LPUVL exposure. The dichroic difference, A_⊥- A_//, of the phenyl C-C stretching vibration of CBDA-ODA, which is polarized along the polyimide chain, has a maximum around 3 J/cm^2. Here A_//and A_⊥ are the absorbance for the IR light polarized parallel and perpendicular to the polarization direction of LPUVL, respectively. The dichroic difference per unit film thickness at 3 J/cm^2 was greater than that of a rubbed CBDA-ODA film with the same film thickness. Although the average IR absorbance, (A_⊥+ A_//)/2, decreases monotonically over the entire measurement range of LPUVL exposure, A_⊥ increases up to 1 J/cm^2. This result shows that the number of polyimide molecules oriented perpendicular to the polarization direction of LPUVL increases. We conclude that the photo-induced orientation contributes to the large surface anisotropy of LPUVL-exposed CBDA-ODA films in addition to the anisotropic photo-induced decomposition.

著者

宇佐美 清章 清原 翔吾 川口 翔平 坂本 謙二

出版者

一般社団法人 日本液晶学会

雑誌

日本液晶学会討論会講演予稿集 (ISSN:18803490)

巻号頁・発行日

vol.2016, 2016

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<p>Photo-aligned films of an azobenzene-containing polyimide (Azo-PI) treated with octadecylamine (ODA) vapor can induce a large pretilt angle. Both average inclination angle and in-plane order of the Azo-PI backbone structure were significantly enhanced by the ODA vapor treatment. In this study, we have investigated the influence of the in-plane order of Azo-PI backbone structure on the pretilt angle generation. Photo-alignment layers with different in-plane molecular order but almost the same average inclination angle were prepared by two different photo-alignment treatments: single oblique angle irradiation of unpolarized light (UP-L) at 45º, and double light exposure of normal angle irradiation of linearly polarized light (LP-L) followed by oblique angle irradiation of UP-L. The difference in the pretilt angles generated by the two different photo-alignment layers was very small. This result suggests that the influence of the in-plane anisotropy of alignment layers on the pretilt angle generation is minor.</p>

著者

宇佐美 清章 清原 翔吾 坂本 謙二

出版者

一般社団法人 日本液晶学会

雑誌

日本液晶学会討論会講演予稿集 (ISSN:18803490)

巻号頁・発行日

vol.2015, pp._2C09-1_-_2C09-2, 2015

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We have investigated the effect of alkyl-amine vapor treatment on pretilt angle generation by photo-alignment films of polyimide containing azobenzene in the backbone structure (Azo-PI). By performing alkyl-amine vapor treatment in preparing photo-alignment Azo-PI layers, the controllable range of the pretilt angle was extended at least up to 38° without appearance of threadlike disclination loops. We found that such a high pretilt angle was induced by the photo-alignment layers with a high inclination angle and narrow orientation distribution of the Azo-PI backbone structure in the out-of-plane direction.