Liquid crystal composition and liquid crystal display device thereof

A liquid crystal composition comprising:

• at least one compound of general formula I:
• and
• at least one compound of general formula II:
• wherein,
• R1 represents C1-5 linear or C3-5 branched, halogenated or unhalogenated alkyl;
• R2 represents —H, halogen, —CN, -Sp2-P2 or C1-12 linear or C3-12 branched alkyl,
• wherein one or more than two nonadjacent —CH2— in the C1-12 linear or C3-12 branched alkyl,
• can each be independently replaced by —CH═CH—, —C≡C—, —O—, —CO—, —CO—O— or —O—CO—, one or more —H can each be independently substituted by —F or —Cl;
• R3 represents —H, halogen, C1-12 linear or C3-12 branched alkyl,
• wherein one or more than two nonadjacent —CH2— in the C1-12 linear or C3-12 branched alkyl can each be independently replaced by —CH═CH—, —C≡C—, —O—, —CO—, —CO—O— or —O—CO— in a manner that —O— are not directly connected to each other, and one or more —H on the C1-12 linear or C3-12 branched alkyl,
• can each be independently substituted by —F or —Cl;
• ring
• and ring
• each independently represents
• or
• wherein one or more —CH2— in
• can be replaced by —O—, and one or more single bond in the ring can be replaced by double bond, wherein one or more —H on
• can each be independently substituted by —F, —Cl or —CN, and one or more —CH═ in the ring can be replaced by —N═;
• A represents
• wherein one or more —CH2— n
• can each be independently replaced by X1 or X2, and one or more single bond in the ring can be replaced by double bond, wherein X1 represents —O— or —S—, X2 represents C1-5 linear alkyl;
• L each independently represents halogen, —CN or -Sp2-P2;
• L1 and L2 each independently represents —H, halogen, C1-3 halogenated alkyl or C1-3 halogenated alkoxy;
• P1 and P2 each independently represents polymerizable group;
• Sp1 and Sp2 each independently represents spacer group or single bond;
• X represents —CO— or —CF2—;
• Z1 and Z2 each independently represents —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —CH2O—, —OCH2—, —CH2S—, —SCH2—, —CF2O—, —OCF2—, —CF2S—, —SCF2—, —(CH2)n—, —CF2CH2—, —CH2CF2—, —(CF2)n—, —CH═CH—, —CF═CF—, —CH═CF—, —CF═CH—, —C≡C—, —CH═CH—CO—O—, —O—CO—CH═CH—, —CH2CH2—CO—O—, —O—CO—CH2CH2—,−CR1R2— or single bond;
• wherein, R1 and R2 each independently represents —H or C1-12 linear or C3-12 branched alkyl, and n represents an integer of 1-4;
• Z3, Z4 and Z5 each independently represents single bond, —CH2CH2—, —CF2CF2—, —CO—O—, —O—CO—, —O—CO—O—, —CH═CH—, —CF═CF—, —CH2O— or —OCH2—;
• r1, r2 and r3 each independently represents 0, 1, 2 or 3, when r1, r2 and r3 each independently represents 2 or 3, L can be the same or different;
• n1 and n2 each independently represents 0, 1 or 2, and n1+n2≥1, when n1 represents 2,
• can be the same or different, when n2 represents 2,
• can be the same or different;
• and
• n3 represents 0, 1 or 2, n4 represents 0 or 1, when n3 represents 2, ring
• can be the same or different, Z3 can be the same or different.