Liquid crystalline media having homeotropic alignment

A LC medium comprising:

• i) a low-molecular-weight, non polymerizable liquid-crystalline component
• and
• ii) one or more polymerizable compounds of the formula I,
• or
• a polymerized component obtainable by polymerization of the polymerisable compound of formula I,
• P-Sp-[A3-Z3]m-[A2]k-[Z2]n-A1-Ra (I)
• in which
• A1, A2, A3 each, independently of one another, denote an aromatic, heteroaromatic, alicyclic or heterocyclic group, which may also contain fused rings, and which may also be mono- or polysubstituted by a group L,
• L in each case, independently of one another, denotes H, F, Cl, Br, I, —CN, —NO2, —NCO, —NCS, —OCN, —SCN, —C(═O)N(R0)2, —C(═O)R0, optionally substituted silyl, optionally substituted aryl or cycloalkyl having 3 to 20 C atoms, or straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, in which, in addition, one or more H atoms may be replaced by F or Cl,
• P denotes a polymerizable group,
• Sp denotes a spacer group or a single bond,
• Z2 in each case, independently of one another, denotes —O—, —S—, —CO—, —CO—O—, —OCO—, —O—CO—O—, —OCH2—, —CH2O—, —SCH2—, —CH2S—, —CF2O—, —OCF2—, —CF2S—, —SCF2—, —(CH2)n1—, —CF2CH2—, —CH2CF2—, —(CF2)n1—, —CH═CH—, —CF═CF—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH—, —(CR0R00)n1—,
• Z3 in each case, independently of one another, denotes a single bond, —O—, —S—, —CO—, —CO—O—, —OCO—, —O—CO—O—, —OCH2—, —CH2O—, —SCH2—, —CH2S—, —CF2O—, —OCF2—, —CF2S—, —SCF2—, —(CH2)n1—, —CF2CH2—, —CH2CF2—, —(CF2)n1—, —CH═CH—, —CF═CF—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH—, —(CR0R00)n1—,
• n1 denotes 1, 2, 3 or 4,
• n denotes 0 or 1,
• m denotes 0, 1, 2, 3, 4, 5 or 6,
• k denotes 0 or 1,
• R0 in each case, independently of one another, denotes alkyl having 1 to 12 C atoms,
• R00 in each case, independently of one another, denotes H or alkyl having 1 to 12 C atoms,
• Ra denotes an anchor group of the formula
• p denotes 1 or 2,
• q denotes 2 or 3,
• B denotes a substituted or unsubstituted ring system or condensed ring system,
• Y, independently of one another, denotes —O—, —S—, —C(O)—, —C(O)O—, —OC(O)—, —NR11— or a single bond,
• o denotes 0 or 1,
• X1, independently of one another, denotes H, alkyl, fluoroalkyl, OH, NH2, NHR11, NR112, OR11, C(O)OH, —CHO,
• where at least one group X1 denotes a radical selected from —OH, —NH2, NHR11, C(O)OH and —CHO,
• R11 denotes alkyl having 1 to 12 C atoms,
• Spa, Spc, Spd each, independently of one another, denote a spacer group or a single bond, and
• Spb denotes a tri- or tetravalent group.