Photosensitive Polyimides for Optical Alignment of Liquid Crystals

Polyimides derived from 1,2,3,4-cyclobutanetetracarboxylic dianhydride and selected aromatic diamines have been found effective as photosensitive materials. These materials have applications as liquid crystals aligners, liquid crystal displays, and related liquid crystal optical elements. The fdm preparation uses a noncontact method that can reduce dust and static charge buildup and improve resolution. 

A reactor was charged with 4-bromo-2-methyl-2-butene (15.Og) and then treated with 110 ml of 40% of aqueous methyl amine, 110 ml of diethyl ether, and 50 ml of methanol. The mixture was extracted, and the extracts were dried over potassium carbonate and distilled 5.25 g of product were isolated, BP = 80-89°C. 

Preparation of 3 [A-(3-Methyl-2-Butenyl)-A-Methyl]Amino-4-Nitroaniline 

The Step 1 product was stirred with 3-fluoro-4-nitroaniline (3.12 g), 6.2 ml of triethyl amine, and 30 ml of A-methylpyrrolidinone at 80°C to 85°C for 10 hours and then extracted with water and diethyl ether. The extract was purified by chromatography on silica gel and the product was isolated. 

The Step 2 product (4.55 g) was treated with tin (II) chloride dihydrate (18.0 g) dissolved in 100 ml of ethanol and 16 ml of lOM hydrochloric acid and then stirred at ambient temperature for 9 hours. The mixture was basified with chilled 20 wt% potassium hydroxide (160 g), extracted with diethyl ether, and purified by chromatography on silica gel the product was isolated as a light amber oil. 

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Title Photosensitive Polyimides for Optical Alignment of Liquid Crystals... 

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