Atomic force microscopic study of rubbed polyimide films

Zhu, Yang‐Ming; Wang, Lin; Zhang, Lu; Yu, Wei; Chen, X. X.; Tang, Jingyi

doi:10.1063/1.113069

Cited by 49 publications

(22 citation statements)

References 10 publications

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“…This phenomenon has been proposed previously to be induced by microgrooves (namely, scratches) generated during rubbing of the film surface. [1][2][3] However, some of the recent publications have suggested that the orientation of polymer chains near the film surface, which are generated by rubbing, plays a key role in aligning LCs at the surface. 4 -11 Others have proposed that both mechanisms are operative together.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of new aromatic polyimides with various side chains containing a biphenyl mesogen unit and their abilities to control liquid-crystal alignments on the rubbed surface

Kim

Ree

Shin

et al. 1999

J. Polym. Sci. A Polym. Chem.

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Section: Introductionmentioning

confidence: 99%

Synthesis of new aromatic polyimides with various side chains containing a biphenyl mesogen unit and their abilities to control liquid-crystal alignments on the rubbed surface

Kim

Ree

Shin

et al. 1999

J. Polym. Sci. A Polym. Chem.

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“…However, the interpretation of atomic resolution AFM images depends critically on the details of the tip-sample interaction [25]. AFM can reveal an image of a rubbed PI film surface, but the resolution is often not sufficient to resolve a single polymer chain [26]. Most of the topographic images of surfaces with adsorbed organic molecules collected with the AFM have been recorded in the contact mode.…”

Section: Introductionmentioning

confidence: 99%

Surface alignment of liquid crystal multilayers evaporated on photoaligned polyimide film observed by surface profiler

Oo¹,

Iwata²,

Kimura³

et al. 2005

Science and Technology of Advanced Materials

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The investigation of the surface alignment of liquid crystal (LC) multilayers evaporated on photoaligned polyimide vertical alignment (PI-VA) film was carried out by means of the novel three-dimensional (3D) surface profiler. We report the first use of the surface profiler to visualize a microscopic image of the monolayer arrangement of LC molecules in contact with the surface of photo-treated PI-VA film. The photoinduced anisotropy of partially UV-exposed PI-VA film can be visualized as a topological image of LC multilayers. It seems that the topology of LC multilayers is indicating the orientational distribution of LC molecules on the treated film. It was found that the periodically photoaligned PI-VA film surface can align an adsorbed LC monolayer and the LC molecular alignment can be extended to the bulk via the epitaxylike LC-LC interaction, i.e. a short-range molecular interaction. With regard to the unexposed PI-VA film surface, noticeable anisotropy in the monolayer alignment was not observed, indicating that the long-range elastic interaction may be responsible for the bulk alignment. The appearance of small droplets in the masked region may be presumably related to the dewetting phenomena. q

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“…Previously, many alignment methods have been proposed to obtain the uniform alignment of LCs [1][2][3][4]. Among these methods, rubbing method is the most widely used and provides the superior electro-optical performance of LC switching [5,6]. However, contact type alignment method causes the electrostatic charges and mechanical damages so that deterioration of the image quality can occur.…”

Section: Introductionmentioning

confidence: 98%

High Speed In-Plane Switching Liquid Crystal Cell by Using Photo Alignment Method

Mun

Cho

Lee³

et al. 2015

Molecular Crystals and Liquid Crystals

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We proposed a fast response time in-plane swithcing (IPS) liquid cryatal (LC) mode in the photo-alignment layer. In order to achieve the fast response time, we first enhanced the anchoring energy of the photo-alignment layer by coating the reactive mesogens (RMs) which can modify the surface condition and also applied the low cell property in the LC cell by using the positive A-plate with same effective retardation as the LC layer.In the experiments, we demonstrated that the coated RM layer can make the strong surface anchoring energy because of its strong polymer chain by the UV exposure and also confirmed the improved response time in the low cell gap IPS cell. As measured results, the response time of the proposed IPS LC cell could be improved over 56.86% and 62.18% compared with that of a conventional photo-aligned IPS cell with/without RM coating, respectively because of the low cell gap property.

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Atomic force microscopic study of rubbed polyimide films

Cited by 49 publications

References 10 publications

Synthesis of new aromatic polyimides with various side chains containing a biphenyl mesogen unit and their abilities to control liquid-crystal alignments on the rubbed surface

Synthesis of new aromatic polyimides with various side chains containing a biphenyl mesogen unit and their abilities to control liquid-crystal alignments on the rubbed surface

Surface alignment of liquid crystal multilayers evaporated on photoaligned polyimide film observed by surface profiler

High Speed In-Plane Switching Liquid Crystal Cell by Using Photo Alignment Method

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