Copolymer for polymer electrolyte, and gel polymer electrolyte and lithium secondary battery which include the same

A copolymer for a polymer electrolyte comprising a compound represented by Formula 2 including a fluorine-based polymer main chain and a unit derived from an acrylate-based monomer or an acrylate-based polymer containing an ion conductive functional group grafted to the fluorine-based polymer main chain:

• wherein, in Formula 2,
• Ra1′ to Rf1′ are each independently hydrogen or a fluorine element,
• R1′ is hydrogen or a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms,
• R4ato R4c are each independently hydrogen or a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms,
• R2′ is hydrogen or an alkyl group having 1 to 5 carbon atoms,
• Y′ is an alkyl group having 1 to 15 carbon atoms which is substituted with at least one halogen element;
• an alkyl group having 3 to 10 carbon atoms which is unsubstituted with at least one halogen element;
• an alkenyl group having 2 to 15 carbon atoms which is substituted or unsubstituted with at least one halogen element;
• —(CH2)d—(CR18R19)e—OH, wherein R18 and R19 each are hydrogen or an alkyl group having 1 to 5 carbon atoms, and d and e are each independently an integer of 0 to 10;—(R7)g—O—(R8)h—CH3, wherein R7 and R8 each are a substituted or unsubstituted alkylene group having 1 to 15 carbon atoms, and g and h each are an integer of 1 to 10;
• or —(CH2)w—NCO, wherein w is an integer of 1 to 10;
• R5a to R5c are each independently an alkyl group having 1 to 10 carbon atoms which is substituted or unsubstituted with at least one halogen element;
• an alkenyl group having 2 to 12 carbon atoms which is substituted or unsubstituted with at least one halogen element;
• a cyclic alkyl group having 3 to 8 carbon atoms;
• a heterocyclic group having 3 to 8 carbon atoms;
• a cyclic ether group having 3 to 8 carbon atoms;
• a heterocyclic ether group having 3 to 8 carbon atoms;
• —(R7)g—O—(R8)h—CH3, wherein R7 and R8 each are a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, and g and h each are an integer of 1 to 10;
• an aryl group having 6 to 12 carbon atoms;
• —(CH2)f—CN, wherein f is an integer of 0 to 10;—(CH2)i—O —CH2═CH2, wherein i is an integer of 0 to 10;—(CH2)i—Si (R9)k(OCH2CH3)3-k, wherein R9 is H, j is an integer of 1 to 10, and k is an integer of 1 to 3;
• or —(CH2)w—NCO, wherein w is an integer of 2 to 10;
• m′ is an integer of 1 to 2,000,
• o1′ is an integer of 0 to 350,
• p1′ is an integer of 0 to 350,
• q1″ is an integer of 1 to 250,
• q2″ is an integer of 0 to 250, with the proviso that o1′ and q2″ are not 0 at a same time,
• n1 is an integer of 1 to 1,500,
• n2 is an integer of 0 to 1,500,
• n3 is an integer of 0 to 1,500, and
• n4 is an integer of 0 to 1,500,
• wherein a weight ratio of the fluorine-based polymer main chain to a unit derived from the acrylate-based monomer or the acrylate-based polymer as the side chain, is in a range of 1:99 to 40:60.