Stability of Photo-Induced Alignment of Azobenzene-Containing Polyimides

ABSTRACT We have examined the change in the molecular orientation of the photo-aligned film of polyimide containing azobenzene in the backbone structure (Azo-PI) by a washing treatment. The Azo-PI films were washed in 2-propanol with an ultrasonic cleaner for 5 min and then in pure water for 5 min. No noticeable change was observed in the in-plane molecular orientation of the photo-aligned Azo-PI films. On the other hand, the in-plane molecular orientation of a rubbed polyimide (poly[4,4′-oxydiphenylene-1,2,3,4-cyclobutanetetracarboximide]) film was relaxed by washing. From these results we conclude that the molecular orientation of the photo-aligned Azo-PI films is more stable than that of the rubbed polyimide film.

[1]  Kenji Sakamoto,et al.  Surface anisotropy of polyimide film irradiated with linearly polarized ultraviolet light , 1998 .

[2]  Hideo Takezoe,et al.  Thermal and Optical Stabilities of Photoisomerizable Polyimide Layers for Nematic Liquid Crystal Alignments , 1998 .

[3]  Kenji Sakamoto,et al.  Alignment of polyamic acid molecules containing azobenzene in the backbone structure: Effects of polarized ultraviolet light irradiation and subsequent thermal imidization , 2003 .

[4]  S. Ushioda,et al.  Effect of a Cleaning Treatment on the Orientational Distribution of Polyimide Backbone Structures in Rubbed Films and on the Pretilt Angle of Liquid Crystals , 2001 .

[5]  Y. Taira,et al.  NEMATIC HOMOGENEOUS PHOTO ALIGNMENT BY POLYIMIDE EXPOSURE TO LINEARLY POLARIZED UV , 1995 .

[6]  S. Ushioda,et al.  Determination of molecular orientation of very thin rubbed and unrubbed polyimide films , 1996 .

[7]  Joachim Stöhr,et al.  Microscopic Origin of Liquid Crystal Alignment on Rubbed Polymer Surfaces , 1998 .

[8]  S. Ushioda,et al.  Inclined Alignment of Polyimide Backbone Structures Induced by Single Exposure of Un-Polarized Light , 2005 .

[9]  Hoi Sing Kwok,et al.  Anchoring properties of photoaligned azo-dye materials. , 2003, Physical review. E, Statistical, nonlinear, and soft matter physics.

[10]  M. Schadt,et al.  Surface-Induced Parallel Alignment of Liquid Crystals by Linearly Polymerized Photopolymers , 1992 .

[11]  H. Yokoyama,et al.  Strong Liquid Crystal Anchoring on Photo-Alignment Copolymer Films Containing ω-(4-chalconyloxy)alkyl Side Groups , 2001 .

[12]  S. Ushioda,et al.  Relation between the molecular orientation of a liquid crystal monolayer and the underlying polyimide film exposed to linearly polarized ultraviolet light , 2003 .

[13]  Martin Schadt,et al.  Optical patterning of multi-domain liquid-crystal displays with wide viewing angles , 1996, Nature.

[14]  M. Barmentlo,et al.  Surface induced liquid‐crystal alignment studied by optical second‐harmonic generation , 1992 .

[15]  Kenji Sakamoto,et al.  Photoinduced inclination of polyimide molecules containing azobenzene in the backbone structure , 2003 .

[16]  M. O'Neill,et al.  Pretilted and grating alignment of liquid crystals by oblique ultraviolet irradiation of polyimide , 2002 .

[17]  J. Koenig,et al.  Spectroscopic Studies of Poly[N,N'-bis(phenoxyphenyl)pyromellitimide]. 1. Structures of the Polyimide and Three Model Compounds , 1980 .

[18]  Mary O'Neill,et al.  Photoinduced surface alignment for liquid crystal displays , 2000 .

[19]  Kazuo Nakayama,et al.  Infrared dichroism and visible-ultraviolet dichroism studies on roller-drawn polypropylene and polyethylene sheets , 1987 .

[20]  Shen,et al.  Investigation of surface-induced alignment of liquid-crystal molecules by optical second-harmonic generation. , 1991, Physical review. A, Atomic, molecular, and optical physics.

[21]  S. Ushioda,et al.  Relation between the molecular orientations of a very thin liquid crystal layer and an underlying rubbed polyimide film , 2000 .

[22]  Wayne M. Gibbons,et al.  Surface-mediated alignment of nematic liquid crystals with polarized laser light , 1991, Nature.