Patent ID: 6816218
Filing Date: 2004-11-09
Classification: G02F

Abstract:
A liquid crystal film with homeotropic alignment wherein said homeotropic alignment is achieved by an aligning layer on a substrate wherein said aligning layer is an Al2O3 layer with a surface sufficiently smooth such that liquid a crystal film formed thereon can be removed in one piece, wherein the liquid crystal film is prepared from a mixture comprising a reactive mesogenic compound of formula IP-(Sp-X)n-MG-R, wherein P is a polymerizable group Sp is a spacer group having 1 to 20 C atoms, X is a group selected from â€”Oâ€”, â€”Sâ€”, â€”COâ€”, â€”COOâ€”, â€”OCOâ€”, â€”OCOâ€”Oâ€” or a single bond; n is 0 or 1, MG is a mesogenic or mesogenity supporting group, according to formula II -(A1-Z1)m-A2-Z2-A3-â€ƒâ€ƒII wherein A1, A2 and A3 are independently from each other 1,4-phenylene in which, in addition, one or more CH groups may be replaced by N, 1,4-cyclohexylene in which, in addition, one or two non-adjacent CH2 groups may be replaced by O and/or S, 1,4-cyclohexenylene or napththalene-2,6-diyl, it being possible for all these groups to be unsubstituted, mono- or poly-substituted with halogen, cyano or nitro groups or alkyl, alkoxy or acyl groups having 1 to 7 C atoms wherein one or more H atoms may be substituted by F or Cl, Z1 and Z2 are each independently â€”COOâ€”, â€”OCOâ€”, CH2CH2â€”, â€”OCH2-, â€”CH2Oâ€”, â€”CH2&boxH;CHâ€”, â€”Câ‰¡Câ€”, â€”CH&boxH;CHâ€”COOâ€”, â€”COâ€”CH&boxH;CHâ€” or a single bond, m is 0, 1 or 2, and R is an alkyl radical with up to 25 C atoms which may be unsubstituted, mono- or polysubstituted by halogen or CN, it being also possible for one or more non-adjacent CH2 groups to be replaced, in each case independently from one another, by â€”Oâ€”, â€”Sâ€”, â€”NHâ€”, â€”N(CH3)â€”, â€”COâ€”, â€”COOâ€” â€”OCOâ€”, â€”OCOâ€”Oâ€”, â€”Sâ€”COâ€”, â€”COâ€”Sâ€” or â€”Câ‰¡Câ€” in such a manner that oxygen atoms are not linked directly to one another, or alternatively R is halogen, cyano or has independently one of the meanings given for P-(Sp-X)n-.