Effects of UV Irradiation and Thermal Treatment of Photo-Degradable Polyimide Layer on LC Alignment

Abstract

The effects of the linearly polarized UV (LPUV) irradiation and thermal treatment of a photo-degradable polyimide (CBDA-ODA) alignment layer (AL) on its AL properties, liquid crystal (LC) alignment, and LCD characteristics have been investigated. The best quality of LC photo-alignment have been induced by the LPUVirradiation with much (about 5~10 times) less dosage than that generating the maximum anisotropy of the AL. A thermal treatment of the LPUV-irradiated AL has effectively removed the undesirable, low-M.W. fragments of the AL generated during the photo-decomposition and increased the stability of the AL, which has resulted in improvement of the LC alignment and the LCD property.

UV irradiation- $$\hbox {H}_{2} \hbox {O}_{2}$$ H 2 O 2 system as an effective combined depolymerization technique to produce

“…Scientists have treated chitosan utilizing different methods in order to improve its solubility and enhance its effectiveness [20]. One potential approach to overcome this problem is the depolymerization of chitosan using acid [21], hydrogen peroxide [22,23], enzyme [24], or ultraviolet light (UV) irradiation [25] in order to obtain oligochitosan. To lower the molecular weight of chitosan, the glucosidal linkages in its skeleton must be broken, which can be accomplished through ultraviolet irradiation (UV irradiation).…”