Alignment layer with reactive mesogens for aligning liquid crystal molecules

A solution for preparing an alignment layer for aligning liquid crystal molecules, said alignment layer comprising:

• (a) a polymer film formed from a polymer or a polymer precursor and (b) at least one reactive mesogen additive in monomeric, oligomeric or polymeric form within said polymer film, wherein said at least one reactive mesogen additive is not said polymer or said polymer precursor used to form said polymer film, said solution comprising:
• a solvent, said at least one reactive mesogen additive, and said polymer or polymer precursor, said polymer or polymer precursor comprising triacetate cellulose or diacetate cellulose, and said at least one reactive mesogen additive having a polymerizable group selected from acrylate, methacrylate, and oxetane, wherein the concentration of said at least one reactive mesogen in said polymer or polymer precursor is 0.5 to 4% by weight
• wherein said at least one reactive mesogen additive is of one of the following formulae:
• wherein
• P1, P2 and P3 are each, independently of each other a polymerisable group,
• Z1 and Z2 are each, independently of each other, —O—, —S—, —CO—, —COO—, —OCO—, —O—COO—, —OCH2—, —CH2O—, —CH2CH2—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH— or a single bond,
• Z3 and Z4 are each, independently of each other —COO—, —OCO—, —CH2CH2—, —CH2O—, —OCH2—, —CH═CH—, —CF═CF—, —C≡C— or a single bond,
• Z5 and Z6 are each, independently of each other —O—, —COO—, —OCO—, —CH2CH2—, —CH2O—, —OCH2— or a single bond,
• Y1 and Y2 are each, independently of each other a polar group,
• R1 and R2 are each, independently of each other an unpolar alkyl or alkoxy group,
• A, B, C and D are each, independently of each other, 1,4-phenylene that is optionally mono-, di- or trisubstituted by L1, L2, L3, L4, L5, L6 or 1,4-cyclohexylene,
• L1, L2, L3, L4, L5 and L6 are each, independently of each other, H, F, Cl, CN or an optionally halogenated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl or alkoxycarbonyloxy group with 1 to 7 C atoms,
• r is 0, 1, 2, 3 or 4,
• x and y are each, independently of each other, an integer from 1 to 12,
• z is 1, 2 or 3, and
• g1, g2, g3 and g4 are each, independently of each other, a single bond, —O—, —COO— or —OCO—.

A method of preparing a laminate, said method comprising:

• providing an alignment layer,
• applying a layer of a polymerizable liquid crystal material onto said alignment layer,
• optionally aligning the liquid crystal material into uniform orientation, and
• polymerizing or crosslinking the liquid crystal material, wherein said at least one reactive mesogen additive is entangled in said alignment layer, and is chemically bound to the layer of liquid crystal material,
• wherein said alignment layer comprises:
• (a) a polymer film formed from a polymer or from a polymer precursor and (b) at least one reactive mesogen additive in monomeric, oligomeric or polymeric form within said polymer film, wherein said at least one reactive mesogen additive is not said polymer or said polymer precursor used to form said polymer film, and wherein, after preparation of said alignment layer, said alignment layer contains unreacted polymerizable groups in said at least one reactive mesogen additive, and
• said alignment layer is prepared by:
• depositing a layer of a solution onto a surface, said solution containing said polymer or polymer precursor, and processing said layer of solution to form said alignment layer, wherein said at least one reactive mesogen additive is incorporated into said layer of solution before said processing, and wherein the concentration of said at least one reactive mesogen additive in said polymer or polymer precursor is 0.5 to 4% by weight.

A solution for preparing an alignment layer, said alignment layer comprising:

• (a) a polymer film formed from a polymer or a polymer precursor and (b) at least one reactive mesogen additive in monomeric, oligomeric or polymeric form within said polymer film, wherein said at least one reactive mesogen additive is not said polymer or said polymer precursor used to form said polymer film, said solution comprising:
• a solvent, said at least one reactive mesogen additive, and said polymer or polymer precursor, said polymer or polymer precursor comprising:
• a polyimide polymer or a precursor of said polyimide polymer,
• wherein the concentration of said at least one reactive mesogen in said polymer or polymer precursor is 0.5 to 4% by weight,
• wherein said at least one reactive mesogen additive is of one of the following formulae:
• wherein
• P1 and P2 are each, independently of each other, a polymerizable group,
• L1 is, in each case independently of each other, H, F, Cl, CN or an optionally halogenated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl or alkoxycarbonyloxy group with 1 to 7 C atoms, and
• x and y are each, independently of each other, an integer from 1 to 12.