Compositions of polymerizable liquid crystals

A composition comprising at least two anisotropic compounds of formula (I)

• wherein
• rings C and D are independently from each other selected from the group consisting of phenyl, biphenyl, naphthyl, cycloalkyl, bicyclohexyl
• ring E is selected from the group consisting of phenyl, biphenyl and naphthyl;
• ring F is selected from the group consisting of the groups of formulae (IIa), (IIb) or (IIc)
• wherein “*” represents the bonding to ring the nitrogen atom of the compound of formula (I);
• X1 and X2 are independently from each other selected from the group consisting of hydrogen, C1-C12 substituted or unsubstituted straight alkyl chain or C3-C12 substituted or unsubstituted branched alkyl chain, C3-C12 substituted or unsubstituted straight chain or branched alkenyl chain and C1-C12 alkoxy, wherein one or more carbon atoms may be replaced by —O—, —COO—, —OCO—, —OOC—, —O(CO)O—, —N—, —NRa—, —CON—, wherein Ra is a C1-C12 alkyl group;
• or
• X1 and X2 independently from each other are represented by the group of formula (III)
• wherein n is an integer between 0 and 24;
• and wherein one or more carbon atoms may be replaced by —O—, —COO—, —OCO—, —OOC—, —O(CO)O—, —N—, —NRa—, —CON—, wherein Ra is a C1-C12 alkyl group;
• and wherein
• PG represents a polymerisable group selected from the group consisting of CH2═C(Ph)-, CH2═CW—COO—, CH2═CH—COO-Ph-, CH2═CW—CO—NH—, CH2═CH—O—, CH2═CH—OOC—, Ph-CH═CH—, CH2═CH-Ph-, CH2═CH-Ph-O—, Rb-Ph-CH═CH—COO—, Rb—OOC—CH═CH-Ph-O— and 2-W-epoxyethyl;
• in which W represents H, Cl, Ph or a lower alkyl and Rb represents a lower alkyl with the proviso that when Rb is attached to a phenylene group (-Ph-) it may also represent hydrogen or a lower alkoxy;
• Y is selected from the group consisting of H, or substituted or unsubstituted alkyl group having 1 to 12 carbon atoms;
• R1, R2 and R3 are independently from each other selected from the group consisting of hydrogen, C1-C12 straight alkyl chain, C3-C12 branched alkyl chain, C3-C12 alkenyl, C1-C12 alkoxy, C3-C12 alkenyloxy, —(CH2)m—C(CH3)3, NO2, CN, COR, —COOR, —OCOR, —CONR′R, —NR′COR, OCOOR, —OCONR′R, —NR′COOR, —F, —Cl, —CF3 and —OCF3;
• in which
• m is an integer between 0 and 12;
• R is selected from the group consisting of hydrogen, an C1-18 alkyl group, an C3-18 alkenyl group with the double bond at 3-position or higher, —(CH2)p—C—(CF3)3, CN and unsubstituted or substituted phenyl ring, wherein the substituent of the phenyl ring is selected from the group consisting of C1-C6 straight alkyl chain, C3-C6 branched alkyl chain, C1-C6 alkoxy, —C—(CH3)3, halogen, —CF3, NO2, CN, COR′″, —COOR′″, —OCOR′″, —CONR″R′″, —NR″COR′″, OCOOR′″, —OCONR″R′″, —NR″COOR′″, —F, —Cl, —CF3 and —OCF3;
• in which
• R″ is selected from the group consisting of hydrogen, a lower alkyl group and a lower alkenyl group;
• R′″ is selected from the group consisting of hydrogen, an C1-18 alkyl group and an C3-18 alkenyl group with the double bond at 3-position or higher;
• p is an integer between 0 and 12;
• R′ is selected from the group consisting of hydrogen, lower alkyl, lower alkenyl and lower alkoxy;
• Z is selected from the group consisting of hydrogen, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, wherein one or more carbon atoms may be replaced by —O—, —COO—, —OCO—, —OOC—, —O(CO)O—, —N—, —NRa—, —CON—, —CO—Rb′-, —NH—Rc, wherein Ra is a C1-C12 alkyl group, Rb and Rc are independently from each other a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or an organic group having 2 to 30 carbon atoms that includes at least one aromatic ring, or a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms;
• with the proviso that both anisotropic compounds are different and comprise two different rings F.