Substituted phenyl trifluoromethyl ethers

A liquid-crystalline phase comprising at least two liquid crystalline components, wherein at least one component is a substituted phenyl trifluoromethyl ether of the formula I

• R.sup.1 --(A.sup.1 --Z.sup.1).sub.n --A.sup.2 --Z.sup.2 --A.sup.3 --OCF.sub.3 I
• in which R.sup.1 is alkyl having 1-18 C atoms in which one or more CH.sub.2 groups may also be replaced by --E--, --O--, --S--and/or --CO--, where two heteratoms are not linked directly to one another, or perfluoroalkyl having 1-18 C atoms in which one or more CF.sub.2 groups may also be replaced by --CH.sub.2 --, --E--, --O--, --S-- and/or --CO--, where two heteratoms are not linked directly to one another,
• E is CH.dbd.CX, CX.dbd.CH, C.tbd.C, CHY, ##STR5## X is Y, CH.sub.3 or H, Y is CN, NCS, NCO or halogen,
• A.sup.1 and A.sup.2, independently of one another, are each 1,4-cyclohexylene, in which one or two non-adjacent CH.sub.2 groups may also be replaced by --O-- and/or S atoms, 1,4-cyclohexenylene, 1,4-bicyclo(2.2.2)-octylene, piperidine-1,4-diyl or 1,4-phenylene, in which one or more CH groups may be replaced by N, which is unsubstituted or monosubstituted or polysubstituted by halogen atoms and/or CN and/or CH.sub.3 groups, [Z.sup.1 and Z.sup.2 are each --CO--O--, --O--CO--, --CH.sub.2 O--, --OCH.sub.2, --CH.sub.2 CH.sub.2 --, --CH.dbd.CH-- or a single bond,]
• Z.sup.1 is --CH.sub.2 CH.sub.2 --, --CH.dbd.CH-- or a single bond,
• Z.sup.2 is --CO--O--, --CH.sub.2 O--, --OCH.sub.2 --, --CH.sub.2 CH.sub.2 --, --CH.dbd.CH-- or a single bond,
• A.sup.3 is a 1,4-phenylene group which is unsubstituted or monosubstituted or polysubstituted by halogen atoms, CN, CH.sub.3 or combination
• and
• n is 0, 1 or 2,
• with the proviso that Z.sup.2 is --CH.sub.2 O--, --OCH.sub.2 --, --CH.sub.2 CH.sub.2 --, --CH.dbd.CH-- or a single bond in the case where n=0 or 1, R.sup.1 =alkoxy and A.sup.1 .dbd.A.sup.2 .dbd.A.sup.3 .dbd.unsubstituted 1,4-phenylene.