Copolyimide, liquid crystal aligning layer comprising the same , and liquid crystal display comprising the same

A polyimide copolymer comprising a repeating unit that is represented by the following Formula 2:

• wherein p is 1 mole % or more and less than 100 mole %, q is 99 mole % or less and more than 0 mole %,
• R3 and R4 are tetravalent organic groups that are the same as or different from each other,
• W3 is selected from the group consisting of the following Structural formulae:
• R5 is a divalent organic group.

A method of producing a liquid crystal aligning layer, which comprises:

• 1) dissolving a polyamic acid copolymer that is represented by the following Formula 6 or 7 in an organic solvent to prepare a liquid crystal alignment solution, and applying the liquid crystal alignment solution on a surface of a substrate to form a coat layer;
• 2) drying the solvent that is contained in the coat layer;
• 3) radiating polarized ultraviolet rays on a surface of the dried coat layer to perform alignment treatment;
• and
• 4) performing heat treatment of the coat layer that is undergone the alignment treatment to perform imidization,
• wherein m is more than 0 mole % and less than 100 mole %, n is less than 100 mole % and more than 0 mole %,
• R1 and R2 are different tetravalent organic groups,
• W1 and W2 are the same as or different from each other and each independently selected from the group consisting of the following Structural formulae:
• wherein p is 1 mole % or more and less than 100 mole %, and q is 99 mole % or less and more than 0 mole %,
• R3 and R4 are tetravalent organic groups that are the same as or different from each other,
• W3 is selected from the group consisting of the following Structural formulae:
• R5 is a divalent organic group.