Polarized Infrared Spectroscopic Studies of Polarized UV-exposed Polyimide Films for Liquid Crystal Alignment

被引：3
作者：
Ha, Ki Ryong [1 ,2 ]
West, John L. [1 ]
Magyar, Gregory R. [1 ]
机构：
[1] Kent State Univ, Inst Liquid Crystal, Kent, OH 44242 USA
[2] Keimyung Univ, Dept Chem Engn, Taegu 704701, South Korea
来源：
MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS | 1998年 / 325卷
基金：
美国国家科学基金会;
关键词：
PI-2555; polarized UV; liquid crystal; infrared spectroscopy; degradation;
D O I：
10.1080/10587259808025380
中图分类号：
O7 [晶体学];
学科分类号：
0702 ; 070205 ; 0703 ; 080501 ;
摘要：
Polarized Fourier transform infrared (FTIR) and ultraviolet-visible (UV-VIS) spectroscopy were used to investigate the cause of liquid crystal alignment on polarized UV (PUV) irradiated polyimide (PI) films. PI films strongly absorb below 350 nm. PUV irradiation of the PI film caused a decrease in the intensity of the original IR absorbance peaks of the PI, due to degradation of the PI molecules, along with the appearance of a new peak at 3261 cm(-1). Because the PI molecules oriented parallel to the direction of UV polarization preferentially degrade, the predominant orientation of the remaining PI molecules after PUV irradiation is perpendicular to the PUV polarization direction. Liquid crystal (LC) molecules align parallel to the predominant orientation of the PI and perpendicular to the PUV polarization direction.
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页码：13 / 32
页数：20
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