Polymerisable LC medium and polymer film with flat optical dispersion

A polymerisable LC material comprising one or more compounds of formula T,

• RT1-(AT1ZT1)m1-GT1-(ZT2-AT2)m2-RT2 T
• wherein
• RT1 and RT2 each and independently from another denotes H or a hydrocarbon group having 1 to 20 carbon atoms, wherein the group may have a substituent group, and in which any carbon atom may be substituted with a heteroatom, and at least one of RT1 and RT2 denotes P-Sp-,
• P denotes a polymerizable group
• Sp denotes a spacer group,
• AT1 and AT2 each and independently and in each occurrence denote a 1,4-phenylene group, a 1,4-cyclohexylene group, a pyridine-2,5-diyl group, a pyrimidine-2,5-diyl group, a naphthalene-2,6-diyl group, a naphthalene-1,4-diyl group, a tetrahydronaphthalene-2,6-diyl group, a decahydronaphthalene-2,6-diyl group, or a 1,3-dioxane-2,5-diyl group, which is unsubstituted or substituted with one or more of groups L,
• L denotes each and independently in each occurrence F, Cl, Br, I, a pentafluorosulfuranyl group, a nitro group, a cyano group, an isocyano group, an amino group, a hydroxyl group, a mercapto group, a methylamino group, a dimethylamino group, a diethylamino group, a diisopropylamino group, a trimethylsilyl group, a dimethylsilyl group, a thioisocyano group, or a linear alkyl group having 1 to 20 carbon atoms or a branched alkyl qroup having 3 to 20 carbon atoms, in which one —CH2— or two or more non-adjacent —CH2— may be each independently substituted with —O—, —S—, —CO—, —COO—, —OCO—, —CO—S—, —S—CO—, —O—CO—O—, —CO—NH—, —NH—CO—, —CH═CH—COO—, —CH═CH—OCO—, —COO—CH═CH—, —OCO—CH═CH—, —CH═CH—, —CF═CF—, or —C═C—, and any hydrogen atom in the alkyl group may be substituted by F, or L may denote a group P-Sp-,
• ZT1 and ZT2 each independently represent —O—, —S—, —OCH2—, —CH2O—, —CH2CH2—, —CO—, —COO—, —OCO—, —CO—S—, —S—CO—, —O—CO—O—, —CO—NH—, —NH—CO—, —OCO—NH—, —NH—COO—, —NH—CO—NH—, —NH—O—, —O—NH—, —SCH2—, —CH2S—, —CF2O—, —OCF2—, —CF2S—, —SCF2—, —CH═CH—COO—, —CH═CH—OCO—, —COO—CH═CH—, —OCO—CH═CH—, —COO—CH2CH2—, —OCO—CH2CH2—, —CH2CH2—COO—, —CH2CH2—OCO—, —COO—CH2—, —OCO—CH2—, —CH2—COO—, —CH2—OCO—, —CH═CH—, —N═N—, —CH═N—, —N═CH—, —CH═N—N═CH—, —CF═CF—, —C═C—, a single bond, or a group represented by —CR01R02O— or —OCR01R02—
• R01 and R02 each independently represent a hydrogen atom, F, Cl, Br, I, or a linear or alkyl group having 1 to 20 carbon atoms or a branched alkyl group having 3 to 20 carbon atoms, in which one —CH2— or two or more non-adjacent —CH2— may be each independently substituted with —O—, —S—, —CO—, —COO—, —OCO—, —CO—S—, —S—CO—, —O—CO—O—, —CO—NH—, —NH—CO—, —CH═CH—COO—, —CH═CH—OCO—, —COO—CH═CH—, —OCO—CH═CH—, —CH═CH—, —CF═CF—, or —C═C—, and any hydrogen atom in the alkyl group may be substituted with F or Cl;
• GT1 denotes a group selected from formulae M-1 to M-8,
• which group is unsubstituted or substituted with one or more of groups L,
• T1 denotes a group selected from formulae T1-1 and T1-2,
• WT1 denotes a group containing an aromatic group and/or non-aromatic group having 1 to 40 carbon atoms, which may be substituted, the aromatic group is a hydrocarbon ring or a heterocyclic ring, and the non-aromatic group is a hydrocarbon group or a group in which any carbon atom in a hydrocarbon group is substituted with a heteroatom provided that oxygen atoms are not directly connected with each other,
• WT2 denotes a hydrogen atom or a linear or alkyl group having 1 to 20 carbon atoms or a branched alkyl qroup having 3 to 20 carbon atoms, in which one —CH2— or two or more non-adjacent —CH2— groups may be each independently substituted with —O—, —S—, —CO—, —COO—, —OCO—, —CO—S—, —S—CO—, —O—CO—O—, —CO—NH—, —NH—CO—, —CH═CH—COO—, —CH═CH—OCO—, —COO—CH═CH—, —OCO—CH═CH—, —CH═CH—, —CF═CF—, or —C═C—, and any hydrogen atom in the alkyl group may be substituted with F, or WT2 may denote a group of 2 to 30 carbon atoms having at least one aromatic group, and the group may be unsubstituted or may be substituted with one or more of groups L, or WT2 may denote a group P-Sp-,
• Y denotes a hydrogen atom, F, Cl, Br, I, a pentafluorosulfuranyl group, a nitro group, a cyano group, an isocyano group, an amino group, a hydroxyl group, a mercapto group, a methylamino group, a dimethylamino group, a diethylamino group, a diisopropylamino group, a trimethylsilyl group, a dimethylsilyl group, a thioisocyano group, or a linear or alkyl group having 1 to 20 carbon atoms or a branched alkyl group having 3 to 20 carbon atoms, in which one —CH2— or two or more non-adjacent —CH2— may be each independently substituted with —O—, —S—, —CO—, —COO—, —OCO—, —CO—S—, —S—CO—, —O—CO—O—, —CO—NH—, —NH—CO—, —CH═CH—COO—, —CH═CH—OCO—, —COO—CH═CH—, —OCO—CH═CH—, —CH═CH—, —CF═CF—, or —C═C—, and any hydrogen atom in the alkyl group may be substituted with F, or Y may represent a group P-Sp-,
• m1 and m2 each independently represent an integer of 1 to 6,
• and
• one or more compounds of formula I,
• wherein
• U1 and U2 are independently of each other selected from
• including their mirror images, wherein the rings U1 and U2 are each bonded to the group —(B)q— via the axial bond, and one or two non-adjacent CH2 groups in these rings are optionally replaced by O and/or S, and the rings U1 and U2 are optionally substituted by one or more groups L,
• Q1 and Q2 are independently of each other CH or SiH,
• Q3 is C or Si,
• B is in each occurrence independently of one another —C≡C—, —CY1═CY2— or an optionally substituted aromatic or heteroaromatic group,
• Y1 and Y2 are independently of each other H, F, Cl, CN or_R0,
• q is an integer from 1 to 10,
• A1 to A4 are independently of each other, in each occurrence selected from non-aromatic, aromatic or heteroaromatic carbocylic or heterocyclic groups, which are optionally substituted by one or more groups R5, and wherein each of -(A1-Z1)m-U1—(Z2-A2)n- and -(A3-Z3)o—U2—(Z4-A4)p- does not contain more aromatic groups than non-aromatic groups,
• Z1 to Z4 are independently of each other, in each occurrence, —O—, —S—, —CO—, —COO—, —OCO—, —O—COO—, —CO—NR0*—, —NR0*—CO—, —NR0*—CO—NR0*—, —OCH2—, —CH2O—, —SCH2—, —CH2S—, —CF2O—, —OCF2—, —CF2S—, —SCF2—, —CH2CH2—, —(CH2)3—, —(CH2)4—, —CF2CH2—, —CH2CF2—, —CF2CF2—, —CH═CH—, —CY1═CY2—, —CH═N—, —N═CH—, —N═N—, —CH═CR0*—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH—, CR0*R00 or a single bond,
• R0* and R00 are independently of each other H or alkyl with 1 to 12 C-atoms,
• m and n are independently of each other 0, 1, 2, 3 or 4,
• and p are independently of each other 0, 1, 2, 3 or 4, and
• R1 to R5 are independently of each other identical or different groups selected from H, halogen, —CN, —NC, —NCO, —NCS, —OCN, —SCN, —C(═O)NR0*R00, —C(═O)R0*, —NH2, —N2R0*R00, —SH, —SR0*, —SO3H, —SO2R0*, —OH, —NO2, —CF3, —SF5, P-Sp-, optionally substituted silyl, or carbyl or hydrocarbyl with 1 to 40 C atoms that is optionally substituted and optionally comprises one or more hetero atoms, or denote P or P-Sp-, or are substituted by P or P-Sp-, wherein the compound comprises at least one group R1-5 denoting or being substituted by P or P-Sp-;
• and wherein the proportion of the one or more compounds of formula I in the polymerisable liquid-crystalline material is in the range of 10 to 99.9% by weight.