Polyimide-based copolymer and polyimide-based film comprising the same

A polyimide-based copolymer comprising a first repeating unit represented by Chemical Formula 1 and a second repeating unit represented by Chemical Formula 2:

• wherein, in Chemical Formula 1,
• each R1 is the same as or different from each other in each repeating unit, and each independently comprises a C6 to C30 divalent aromatic organic group containing at least one —O— linking group, and the aromatic organic group exists alone, or two or more aromatic organic groups are bonded to each other to form a condensed ring, or two or more aromatic organic groups are linked by a single bond, a fluorenylene group, —O—, —S—, —C(═O)—, —CH(OH)—, —S(═O)2—, —Si(CH3)2—, —(CH2)p— (wherein 1≤p≤10), —(CF2)q— (wherein 1≤q≤10), —C(CH3)2—, —C(CF3)2—, or —C(═O)NH—;
• each R2 is the same as or different from each other in each repeating unit, and each is independently —H, —F, —Cl, —Br, —I, —CF3, —CCl3, —CBr3, —Cl3, —NO2, —CN, —COCH3, —CO2C2H5, a silyl group containing three C1 to C10 aliphatic organic groups, a C1 to C10 aliphatic organic group, or a C6 to C20 aromatic organic group;
• n1 and m1 are each independently an integer of 0 to 3;
• each Y1 is the same as or different from each other in each repeating unit, and each is independently a C3 to C10 aliphatic organic group;
• and
• each E1 is independently a single bond or —NH—,
• wherein, in Chemical Formula 2,
• each Y2 is the same as or different from each other in each repeating unit, and each is independently a C6 to C30 divalent aromatic organic group containing at least one trifluoromethyl group (—CF3), and the aromatic organic group exists alone, or two or more aromatic organic groups are bonded to each other to form a condensed ring, or two or more aromatic organic groups are linked by a single bond, a fluorenylene group, —O—, —S—, —C(═O)—, —CH(OH)—, —S(═O)2—, —Si(CH3)2—, —(CH2)p— (wherein 1≤p≤10), —(CF2)q— (wherein 1≤q≤10), —C(CH3)2—, —C(CF3)2—, or —C(═O)NH—;
• E2, E3, and E4 are independently a single bond or —NH—;
• and
• each Y3 is the same as or different from each other in each repeating unit, and each is independently a divalent linking group derived from at least one compound selected from the group consisting of diacyl halide, dicarboxylic acid, and dicarboxylate in the form of —C(═O)-A-C(═O)—,
• wherein A of Y3 is a C6 to C20 divalent aromatic organic group, a C4 to C20 divalent heteroaromatic organic group, or a C6 to C20 divalent alicyclic organic group, and two of —C(═O)— are bonded at a para position with respect to A.