MXPA99000938A - Liquid crystal composition and alignment layer - Google Patents

Abstract

A surface for the alignment of liquid crystals containing directionally-linked groups and compounds useful for preparing such surfaces are disclosed.

Description

COMPOSITION OF LIQUID CRYSTAL AND ALIGNMENT LAYER BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION The present invention relates to a new directionally bonded surface useful for the alignment of liquid crystals. Methods for preparing this new surface are also described, as well as a preferred method wherein a polymerizable, self-assembled adsorbed layer of high resolution pattern is polymerized through polarized radiation. In this way, the present invention relates to the development of a new alignment procedure for liquid crystals that do not require mechanical rubbing and that is suitable for flat panel displays. The procedure creates, through a combination of chemisorption and photopolymerization, an anisotropic surface with "molecular grooves", which guide the liquid crystal molecules in their orientation. The present invention also provides novel compounds for use on the surfaces and process herein. 2. BACKGROUND Flat panel liquid crystal display (LC) devices typically require substrates, which provide uniformly flat and uniaxial orientation of liquid crystalline molecules. Currently, said alignment is achieved by initially placing by rotation a polymer coating (polyamide, polyimide, etc.) on a substrate followed by mechanical rubbing of the polymer surface with cotton, rabbit skin, etc. This technique, however, presents inherent problems, since it is difficult to obtain a predictable uniform alignment over large areas. In addition, the rub creates both charges and dust. These loads in turn lead to the failure of the LC devices due to, for example, the reduction of conduction surfaces, etc., and the dust can provide defective sites. Therefore, there is a current industrial need for a surface that promotes uniaxial liquid crystal alignment (ie, both a flat alignment (an alignment orientation where the long axis (or average conductor) of the liquid crystal is not perpendicular to the plane of the substrate surface), as a homeotropic alignment, where the liquid crystal molecules are perpendicular to the surface of the substrate), without the need to mechanically rub the surface of a substrate, and a simple technique to produce said surface . Colorless substrates that align liquid crystalline molecules are also desirable for high contrast applications, etc. The current aspects to address the problems encountered with rubbed surfaces include the coating of layers of Langmuir-Blodgett (LB) on substrates, and the polymerization or irradiation of substrates that have been coated with polymers with polarized light. In the film aspect of LB, major difficulties are encountered, which have not yet been overcome; (i) it is very difficult to extend an LB process for manufacturing purposes, and (ii) a useful alignment layer is manufactured only through the deposition of layer by layer of monolayers on a substrate on the adjacent surface of the air-water of a LB. Since the monolayer of the present in the adjoining air-water surface in an LB tundish is not in its thermodynamically stable state, the alignment layer obtained does not have long term mechanical and thermal stability. LB layers also generally contain inhomogeneities or defects domains within the plane of the film. This makes it difficult to obtain the uniaxial alignment of a liquid crystal composite over a large area. Furthermore, it is known that the LB films have a considerable degeneration with respect to the inclination of the LB-forming molecules within the plane of the film. As a consequence, it is not possible to obtain specific pre-tilt directions on the surface of the substrate. The aspects of the type of spin-cast conduction polymer films are being investigated. In the case of the conductive polymer appearance, conductive polymer films, the idea is to replace the polyimide layer by the conducting polymer as the alignment layer. This aspect is to demonstrate its viability for uniformity of alignment. In this way, there is a current need for a new frictionless alignment procedure, which can be reproduced, can be applied to both TN and STN devices and which can be easily extended and inserted into a technology / manufacturing process existing. Hercules (E.U.A. 5,032,009; E.U.A. 4,974,941; E.U.A. 5,073,294; Nature Vol. 351, May 19, 1991; Liquid Crystals, Vol. 12, No. 5, 869, 1992; Newsletter of the Int. Lia. Crvstl. Soc, ("Liquid Crystals Today"), Vol. 4, No. 2 1994, all incorporated herein by reference) has reported the alignment of liquid crystals optionally containing dyes with polarized light and the preparation of a surface made of an isomerizable dye, which is first dispersed in a polymer and subsequently irradiated with polarized light. Neither the same liquid crystal, dye, nor the host polymer, is covalently bound to the substrate, and the alignment surface is unstable; the heat and / or the subsequent irradiation changes or erases any orientation alignment effects initially obtained. Schadt et al. (Jpn. J. Appl. Phys., Vol. 31, Pt 1, No. 7, page 2155 (1992); EP 525,477; EP 525,473 and EP 525,478, all incorporated herein by reference) have also reported alignment surfaces prepared through the irradiation of polymers which have, attached to the base structure of the polymer, polymerizable pendant groups, using polarized light. However, these surfaces require pre-polymerization, and, as those described above, are not covalently bound to a substrate surface. In addition, when polymer layers are made as those of Schadt and thin Gíbbons to reduce the driving voltage, very small holes arise, which cause defects and short circuits. Finally, lchimura (Abstract from the Tawiguchi Conference, (Japan), 1994, incorporated herein by reference) has used polarized light to orient polymers bearing side chain azobenzenes. The polymers were applied to substrates using an LB technique and a spin coating technique, and showed the alignment of liquid crystals in contact with them. However, these films, as well as those of Schadt and Gibbons, are not attached to the surface of the substrate, and present the general disadvantages discussed above for such films as well as those discussed with respect to LB films. In this way, the need remains for an alignment surface based on a non-rubbed, LB-free tundish, which can be easily produced and used in liquid crystal devices that require alignment layers. The present invention provides said surface. There is also a need for new useful compounds on the surfaces of the present and methods.

COMPENDIUM OF THE INVENTION Accordingly, it is an object of the present invention to provide a surface for uniaxial plane alignment, homeotropic alignment, etc., of liquid crystal molecules in contact therewith, the pre-tilt angle? of aligned liquid crystals varying from 0o < _? < _ 90 ° (measured as the angle that the long axis (director) of the liquid crystalline molecule makes with the surface plane of the substrate). It is another object of the present invention to provide liquid crystal display devices, spatial light modulators, phase modulators, non-linear optical devices, etc., comprising substrates that provide flat alignment, homeotropic alignment, etc., of crystalline molecules in contact with them. It is another object of the present invention to provide a simple method for producing a surface that provides the uniaxial flat alignment, homeotropic alignment, etc., of liquid crystalline molecules in contact therewith. Is it still another object of the present invention to provide a liquid crystal alignment surface that is color or colorless, which provides the control of the pre-tilt angle? of the liquid crystal molecules in contact therewith from 0 ° to 90 °, and which provides uniaxial plane alignment (representing that for all those other than 0 ° and 90 ° all or substantially all liquid crystalline molecules in contact with the surface are tilted in the same direction). It is another object of the present invention to provide novel compounds useful in the surfaces and methods of the present invention. It is another object of the present invention to provide novel compounds, which provide surfaces with improved pre-tilt properties. These and other objects, which will be apparent from the following detailed description, have been achieved through the discovery of the inventors of a surface containing anisotropic chemistry and geometrical aspects that guide liquid crystalline molecules in contact with it in orientations. preferred and with angles of inclination? from 0 ° to 90 °. The inventors have also discovered that compounds of the formula: [Xm] - [S] "- [P] 0 1 wherein: X is a chemical functional group capable of adsorption, absorption or chemisorption to a surface or a substrate, S is a separator, and P is a directionally linkable group of formula (I): wherein each of R1, R2, R3, R4, and R5 is H, CnH2n + 1, OCnH2n +?. or NO2, where n is an integer from 1 to 8, provided that not all of R1, R2, R3, R4, and R5 are H, and n, m and o of the formula [Xm] - [S] "- [P ] 0 all are integers greater than or equal to 1, and m > . n and o > . n, provide surfaces that exhibit improved pre-tilt properties. Also preferred are compounds of the formula: [Xm] - [S] n- [P] o 1 wherein X and S are each as defined above, and P is a directionally linkable group, and n of formula 1 is either 0 or an integer greater than or equal to 1, myo each are integers greater than or equal to 1, where m > n of formula 1 and o > n of formula 1, where P has the following formula (IA): wherein each of R, R2, R3, R4, and R5 is H, Br, Cl, F, CF3, CN, CN, -CO2CnH2n + 1 linear or branched and racemic or chiral, CnH2n + 1 linear or branched and racemic or chiral, OCH2CnF2n + 1, NO2 or OH, wherein n of said groups R -R5 is an integer from 1 to 12.

BRIEF DESCRIPTION OF THE DRAWINGS A more complete appreciation of the invention and many of the concurrent advantages thereof will be readily obtained as it is better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, wherein: Figure 1 is a schematic representation of a process for effecting the chemisorption of silane molecules on a surface. A substrate is submerged in a solution containing silane molecules. The silanes covalently bind to the surface; Figure 2 shows the structures of hydrophobic silanes named in the specification. When they are chemisorbed on a surface, these silanes promote a perpendicular (homeotropic) alignment of LC molecules; Figure 3 shows the structures of some silanes investigated for LC alignment. All have one group -NH2 (amine) at the end of the molecule and one trialkoxy silyl group at the other end; Figure 4 shows the optical textures obtained with E-63 on an ITO substrate treated with different hydrophilic silanes; Figure 5 is a schematic representation of one embodiment of the different steps involved in the alignment procedure of the invention, Step 2: optional modification of the chemosorbed silane layer (DETA, EDA, APS or ABTE) and joining of the photopolymerizable group (FIG. cinnamoyl chloride); Step 3: irradiation through polarized UV light and formation of oligomer pairs (including β-truxamides); Figure 6 is the UV absorption spectrum of the chemosorbed silane layer after attachment of the cinnamoyl chloride unit. (a) DETA, (b) EDA and (c) ABTE. Figure 7 is the UV absorption spectrum of the chemisorbed silane layer before and after photopolymerization. Figure 8 shows the liquid crystal alignment obtained with a flat glass cell having on it a directionally "polymerized" surface Both directions are shown to be polymerized and unpolymerized LC molecules are aligned (dark region) in a flat orientation uniform in the polymerized regions Figure 9 shows the liquid crystal alignment in a twisted nematic cell (TN) comprising directionally bonded surfaces placed as coatings on the substrates The base substrates consist of pure ITO glass Both coated regions are shown directionally bound and unbound The liquid crystalline (LC) molecules are aligned in a uniform planar orientation in the directionally linked regions; Figure 10 shows the liquid crystal alignment in a twisted nematic cell comprising directionally bonded surfaces placed as surface coatings; e the substrates. The glass substrates coated with base ITO are first coated with a passivation layer of Si02, which has a thickness of 690Á. Both regions are shown directionally linked and not linked. The LC molecules are aligned in a uniform planar orientation in the polymerized regions; Figure 11 shows the electro-optical characteristics of a TN cell with a coatings directionally bonded on the substrates. The underlying substrates consist of pure ITO glass; Figure 12 shows the electro-optical characteristics of a TN cell with a directionally bonded coating on the substrates. The underlying substrates consist of passive ITO; Figure 13 shows some of the many alternative directionally linkable groups useful in the surface and method of the present. X represents an absorbable, adsorbable, chemisorbent, etc. end of the molecule. The separator here is an individual link; Figure 14 shows a synthetic scheme for the synthesis of certain compounds of the present invention; Figure 15 shows a variety of chromophores synthesized for the modification of the chemisorbed layer according to the invention; Figure 16 shows a synthetic scheme for the synthesis of certain compounds of the present invention which contain directionally linkable moieties; Figure 17 shows the experimental design used to measure the pre-tilt angle; Figure 18 shows the results of a pre-tilt angle measurement for a surface according to the present invention; Figure 19 shows the results of a pre-tilt angle measurement for a surface according to the present invention; Figure 20 shows the results of a pre-tilt angle measurement for a surface according to the present invention; Figure 21 shows the results of a pre-tilt angle measurement for a surface according to the present invention; Figure 22 shows the results of a pre-tilt angle measurement for a surface according to the present invention; Figure 23 shows the results of pre-tilt measurements for different surfaces with different chromophores attached to the chemisorbed layer. The commercially available E7 mixture was used as liquid crystal; Figure 24 shows the results of pre-tilt measurements for different surfaces with different chromophores attached to the chemisorbed layer. The commercially available ZL1 4792 mixture was used as the liquid crystal; Figure 25 shows the results of pre-tilt measurements for different surfaces with different chromophores attached to the chemisorbed layer. The commercially available E7 and ZL1 4792 mixtures were used as liquid crystal; Figure 26 shows the pre-tilt chain length dependency for commercially available E7 and ZL1 4792 blends using 4-alkoxy chromophores in the alignment layer; Figure 27 shows the results of pre-tilt measurements for different surfaces with different chromophores attached to the chemisorbed layer. The commercially available E7 and ZL1 4792 mixtures were used as liquid crystal; and Figure 28 shows the results of pre-tilt measurements of alignment layers with fluorinated substitution.

DETAILED DESCRIPTION OF THE PRESENT INVENTION The inventors of the present invention have discovered that an "adsorbed" anisotropic anisotropic linked layer (representing chemisorbed, adsorbed, absorbed, etc.) produces a surface having superior alignment properties. Their discovery includes the formation of layers on a substrate surface through chemisorption, optionally followed by chemical modification of the chemisorbed layer through the attachment of a directionally linkable group thereto, and, finally, the creation of an anisotropic surface. through directional linkage, for example, polarized radiation. Their discovery also includes the formation of an alignment layer containing molecules with both chemo-absorbable and directionally linkable groups, followed by directional entanglement using polarized radiation. These methods can create an anisotropic surface alignment layer that provides uniform flat alignment of LC molecules without any rubbing. The alignment surface of the invention is preferably a directionally bound layer of molecules adsorbed, absorbed or chemically bound to a substrate. By "layer", the inventors mean more than one molecule, and the invention is not limited to a monolayer, a continuous layer, etc.

The formation of covalent attachment of the layer molecules to the substrate is preferred (ie, chemisorption). For example, an -OH group on the surface of a glass substrate provides a site for the attachment of a chemosorbable molecule. Therefore, chemisorption, as used herein, provides an alignment layer with long-term thermal and mechanical stability. See Figure 1 for chemosorption of silanes. In particular, the alignment surface of the present invention comprises a layer directionally linked with anisotropic (ie, molecular) chemistry and, it is believed, geometrical aspects. These aspects are provided through an adsorbed (ie, adsorbed, absorbed, preferably chemisorbed, etc.) layer or layers, which comprise one or more compounds having the following general formula: wherein: X is a chemical functional group capable of adsorption, absorption or chemisorption to a surface or a substrate, S is a separator, and P is a directionally linkable group. X is a group that adsorbs surfaces, particularly surfaces and substrates used in devices that require aligned liquid crystals (e.g., glass; glass coated with ITO; ITO coated glass with passivation layer, preferably SiO2; ITO coated plastic; plastic coated with ITO with passivation layer (particularly Si02), boron silicate coated with ITO, boron silicate coated with ITO with passivation layer (particularly Si02), polymer surfaces, diamond surfaces, materials containing micro holes, wafers of silicone optionally comprising a predetermined pattern; silicon wafers in pattern after adsorption, absorption or chemisorption of the compounds described above, etc.). It is understood that the aforementioned passivation layers can conveniently be a top layer or below an ITO layer. Of course, substrates other than those currently used in liquid crystalline devices can also be coated with the compounds described above. Examples of useful surfaces include gold, silver, copper, mirror surfaces, MgFe2, chromium, platinum, palladium, mica, aluminum oxide, aluminum, amorphous hydrogenated silica, gallium arsenide, polysilicon, sulfides including cadmium sulfide films, selenides , silver bromide, oxidized metal surfaces, metal surfaces, plastic (polymer) surfaces, etc. In addition to the silanes depicted in Figure 1, other suitable X groups include any functional group capable of adsorption to the surfaces described above. Chemical groups to covalently attach to the surface of the substrate (chemisorption) are preferred. Examples include any group that performs a Si-O bond with a hydroxyl group surface including, for example, SiR2OH, where R is C1 to C10 alkoxy or C1 to C10 alkyl, -If (OH) 3, mono / di / trialkoxy silanes such as (C 1 -C 10 alkoxy) 3 SiCl, (C 1 -C 10 alkoxy) 2 SiC 2 or (C 1 -C 10 alkoxy) SiCi 3 , and mono / di / trialkyl silanes such as (C 1 -C 10 alkoxy) 3SiCl, (C 1 -C 10 alkyl) 2SiCl 2 or (C 1 -C 10 alkyl) SiCl 3. Other examples of X include a carboxyl group (COO); phosphorus-containing groups, a thiol group; an alcohol group; a carbonyl group; a met (acrylate) group; titanates; zirconates; a thiocyanate group; a group of (meth) acrylic acid; an isocyanate group; an isothiocyanate group; an acyl cyanate group; an acyl thiocyanate group; etc., each group X being selected in order to adsorb the desired substrate, preferably chemisorption. When possible, the group X can be chiral (for example, a trialkoxysilane group having different alkoxy groups). It is also possible that a single layer forming molecule of formula 1 may contain two or more of the above chemically functional X groups, and that one or more are used for adsorption to the surface. Thus, n in the above formula can be an integer greater than 1, and preferably is 1-4, most preferably 1 or 2. In addition, the X groups in different layer-forming molecules can be linked together with others to adsorb to the substrate. See, Figure 1, wherein the oligomers form X groups. S in the above formula is a spacer group. In addition to the spacer groups described in Figure 3 (hydrocarbon chains and hydrocarbon chains interrupted by one or two NH groups), other spacer groups can be used. Suitable spacer groups include any chemical moiety that separates X from P and does not prevent X and P from performing their functions. For example, suitable spacer groups include an individual bond and an alkyl group of 1 to 30 carbon atoms or 3 to 30 branched carbon atoms, each optionally interrupted, when there are at least two carbon atoms, per one or more aromatic groups, peptide groups, heterocyclic groups, NH, NR, wherein R is a hydrocarbon group of 1 to 18 carbon atoms, O, S, COO, oxygenated sulfur, i.e. SOn, wherein n is 1-4 , CO, phosphorus, oxygenated phosphorus such as phosphine group, phosphate, phosphite, etc., which are preferably not adjacent. The spacer groups may be optionally substituted, for example, with hydroxyl, nitro, halogen, those substituents listed below, etc. Other suitable S groups include an aromatic group of 6 to 70 carbon atoms (preferably of 6 to 12 carbon atoms, phenylene, naphthylene, biphenylene, etc.) optionally substituted with alkyl, hydroxyl, nitro, halogen, etc., groups. a heterocyclic group of 3 to 30 carbon atoms (preferably of 5 to 30 carbon atoms) optionally substituted with alkyl, hydroxyl, nitro, halogen, etc. groups, and a cyclic, saturated, or 3 to 30 carbon hydrocarbon group partially unsaturated optionally substituted with hydroxyl, halogen, nitro, etc., and includes substituted or unsubstituted steroids such as cholesterol, etc. It is emphasized that any separator that links X and P and does not deny its functions can be used. The separator of the present invention can be chiral. Preferably, the separator separates X from P from 1 to 1000 angstroms, preferably from 2 to 70 angstroms, most preferably from 3 to 30 angstroms, including 5, 10, 15, 20 and 25 angstroms and all scales between them, and chemically Is it designed to provide a pre-tilt angle? Preferred preferably liquid crystal molecules uniaxially oriented in contact with the surfaces of the invention of 0 ° <; ? < 90 ° (ie, pure flat to homeotropic alignment). A layer-forming molecule of formula 1 can carry more than one spacer group and preferably has as many spacers as directionally linkable groups exist. In this way, n is an integer of 1 or more, preferably 1-4, most preferably 1 or 2. Preferably, n is equal to or less than or (the number of groups P). P in the above formula is a group capable of directionally linking to another group P. Directional binding includes dimerization, oligomerization, polymerization, photoreactions including insertions, isomerizations, Norish reactions I and II, etc., where at least two P groups they are anisotropically linked. Also included are groups capable of directional charge transfer, ionic bonding, hydrogen bonding, etc. The P groups encompass all functional groups capable of being directionally linked (ie, anisotropically) to another group in preference to a neighboring or near P group. In addition to the cinnamoyl groups described in Figure 5, any suitable directionally linkable groups can be used including those illustrated in Figure 13 and any other group capable of directional linking to a neighboring P group through polarized radiation, heat, surface manipulation. with a scanning tunneling microscope, atomic force microscope, etc. These groups can be directionally linked in any way, representing that anisotropic dimer formation, oligomer formation, polymer formation, charge transfer complex formation, ion attraction, etc., all produce useful surfaces that provide alignment of LC. In addition, the P-P 'directional link can be chiral. The directional linking of the groups P is preferably effected through linear, circular or elliptically polarized UV light, or a combination thereof including a combination of polarized or non-polarized UV light. In addition, the radiation in the VIS or IR scale can be used. A preferred embodiment of the present invention is a surface coated with a chemisorbed layer of molecules [Xm] - [S] n- [P] 0, which have been polymerized with polarized UV radiation to form mostly dimers. Preferred adsorbable molecules according to the invention have m = n_o = 1. However, since a layer-forming molecule of the present invention can carry more than one group P, or it can be an integer greater than 1. Although each separator preferably has a group P, more than one group P can be present in each separator. In this way, or is preferably greater than or equal to n and preferably is an integer of 1-4. When a layer-forming molecule of formula 1 has two or more P groups, the P groups on a molecule can be directly linked together, or some or all of the various P groups on a molecule can be directionally linked to P groups on other molecules. With two or more P groups on a single molecule, a combination of these effects can be used. For example, two groups P on a molecule can be linked directionally, followed by directional linkage with a group P on a neighboring molecule. By "neighbor" is meant any molecule with a group P that reacts with the group P of the invention. The compounds [Xm] - [S] n- [P] o of the invention are prepared through simple organic reactions well known and within the experience of the experts and are explained in, for example, Introduction to Orqanic Chemistry, A Streitwieser and C. Heathcock, Macmillan, 1976; Rea ents for Orqanic Svnthesis, Fieser and Fieser, John Wiley and Sons, 1967 and subsequent volumes; Survev of Orqanic Syntheses, John Wiley and Sons, Vols. I and II; and Advanced Orqanic Chemistry, March, Wiley, 1985, all incorporated herein by reference.

The anisotropic surfaces of the invention can be made as thin as a layer of molecules of formula 1 or several multiples thereof. Any thickness is acceptable. A preferred thickness is from 3 to 3000 angstroms. The surfaces of the invention can be prepared through processes that include electric shielding, magnetic field, solvent flow, etc., molecule alignment [Xm] - [S] n- [P] or followed by directional binding with heat, light, chemical activation, etc., and are not limited to those proposed by the procedure described below. Those surfaces produced by the method described below are preferred. The preferred process of the present invention comprises two or three steps: (i) formation of an adsorbed, preferably chemisorbed layer or layers of molecules [X] - [S] n- [P] or on a substrate (or molecules [Xm] - [S] n- [P] o if desired), (ii) optional chemical modification of the adsorbed molecules to provide at least one spacer group S and at least one directionally linkable group P therein, if not present none before adsorption, and (ii) directional linking using any of the methods described above, preferably using polarized radiation, particularly polarized UV radiation. Step (ii) may be omitted if the material used in step (i) already comprises a separator and a directionally linkable group. - The three possible steps involved in the process of the invention are shown schematically in Figures 1 and 5. First an adsorbed (preferably chemisorbed) layer or layers of molecules that carry no group P is placed on the surface of a substrate as a base, which then becomes photosensitive through the union of a group P (in this case, a UV chromophore). Finally, an anisotropic surface is created through photopolymerization with polarized UV light, where the polymerizable groups of neighboring (presumably adjacent) molecules are joined together, the direction of the polymerization being directed through the polarization direction of the radiation . They include UV radiation, IR radiation, visible radiation, etc. The final result is a surface that contains anisotropic and, it is believed, geometric molecular aspects, whose direction dictates the direction of orientation for the long axis, or average conductor of the liquid crystal molecules. Preferred methods for carrying out the invention are described below. (i) Preparation of the substrate: The first step of the adsorption process of the invention, preferably chemisorption, preferably includes the preparation of the surface of the substrate. This procedure is applied to glass, glass coated with ITO, silicon wafers, etc., and is simply the cleaning of the surface of the substrate. In a preferred embodiment, the sound is applied to the substrate twice in chloroform. Then the substrate is washed in 1: 1 HCl / methanol for 30 minutes (one step is omitted for the glass coated with ITO), followed by 3x rinsing with distilled water. It is then washed in concentrated H2SO for 30 minutes and again rinsed three times with distilled water. The substrate is heated in distilled water at 80-100 ° C for about 5 minutes and then cooled. Another method for preparing substrates for chemoadsorption is the use of an oxygen plasma for 5 minutes. After said treatment, the substrate is ready for the chemisorption, adsorption, absorption, etc., of the compounds of the general formula [Xm] - [S] n- [P] o or [Xm] - [S] not [Xm] ] if no polymerizable group or separator is present. (ii) Bonding of the adsorbed layer: A solution for adsorption, absorption, chemisorption, etc., can be prepared or other adsorption methods known in the art can be used. A typical preferred chemosorption solution contains 1% by volume of the desired chemisorbable material, 5% by volume of distilled water and 94% by volume of a solution of 1mM acetic acid in methanol. The substrate to be treated was immersed in this solution and allowed to stand for 5-15 minutes at room temperature. The solution was then emptied, and the substrate was rinsed three times with fresh methanol. The substrate can then be baked at 120 ° C for 15 minutes to dry. The chemisorbent molecules are chemically bound to the surface: that is, the molecules are covalently bound to it. The chemisorbed layer is then ready for chromophore binding, if no chromophore is present in the material in the first place. The layer can be adsorbed in a particular pattern. (iii) Bonding of the separator and group directionally bondable to the initially adsorbed layer: In this step (optional since the adsorbed, absorbed, chemisorbed molecule to the surface in (ii) above may already possess a separator and a polymerizable group) a group directionally linkable and, if desired, a separator other than an individual link is attached to the adsorbed layer. The substrate with the adsorbed layer is immersed in a solution containing a compound with, for example, a separator linked to a directionally bondable group and a chemically reactive group for reaction with the initially adsorbed layer, such as cinnamoyl chloride. Acetonitrile can be used as the solvent. The substrate is then allowed to stand in the solution for one hour in the dark. This ensures the attachment of the separator and, for example, the polymerizable chromophore to the adsorbed layer. In four specific modalities using APS, ABTE, EDA and DETA, the chemical modification was determined with cinnamoyl chloride through the UV adsorption peak seen at 275 nm (see, for example, Figure 6) The directionally interlaced group, etc., It can be provided in a pattern if desired. (iv) Directional interlacing: The last step of the method of the invention is directional entanglement, preferably dimerization, oligomerization, directional polymerization, etc. Oligomerization, dimerization and directional polymerization are preferred. In a preferred embodiment, a substrate with a photopolymerizable chemosorbed layer is irradiated with polarized UV radiation to obtain an anisotropic surface. A typical dose of UV radiation is about 3 J / cm2 for about 15 minutes. As the person skilled in the art knows, time varies with the intensity of the lamp, proximity of the substrate to the lamp, etc. The dose can also vary conveniently. This treatment leads to a photo-induced reaction between photopolymerizable or photodimerizable groups of, presumably, adjacent chemo-adsorbed molecules, thus forming a cyclobutane ring (in the case of polymerizable cinnamic acid derivatives). See Figure 5. The existence of these ß-truxamide pairs was ascertained through the UV absorption spectrum: the photopolymerization that results in the formation of the dimer pair results in a drastic reduction in the peak at 275 nm and an increase in UV absorbance at 193 nm due to the presence of cyclobutane rings (Figure 7). Pattern formation can occur through binding using a light pattern that passes through a mask, etc. Although not intended to be attached to any particular theory, it is believed that the formation of the directionally bonded surface results in a highly anisotropic surface. The polymerization structure, or perhaps more correctly in the case of cinnamic acid derivatives, the directionally dimerized structure, it is believed that it will be oriented in a preferred individual direction, dictated by the direction of the polarization of the light used to effect the directional entanglement. The method of the invention in this manner creates an anisotropic, bonded, permanent surface layer on a substrate through a procedure that involves no rubbing or no host-guest interaction. The surface of the invention is stable to, for example, heat and light and solvents (methanol, acetonitrile, water, etc.), maintaining the orientation of liquid crystalline molecules in contact with it even after exposure to high temperature or UV radiation during extended periods. Depending on the compound of formula 1 used, the surface of the invention may be colorless or colored, showing absorption on the visible scale from 0% to 100%. In another embodiment, the present invention provides a preferred group of compounds, wherein the group P has the formula (I): (I) wherein each of R1, R2, R3, R4 and R5 is independently H, CnH2n +? linear or branched, OC "H2"., linear or branched, or NO2, where n is an integer from 1 to 8, and where at least one of R1, R2, R3, R4 and R5 is not H. present invention also provides a preferred group of compounds wherein the group P has the formula (IA): wherein each of R1, R2, R3, R4 and R5 is H, Br, Cl, F. CF3, CN, NC, -CO2CnH2n + 1 linear or branched and racemic or chiral, CnH2n +. linear or branched and racemic or chiral, OCnH2n +? linear or branched and racemic or chiral, OCH2CnF2n +?, N02 or OH, where n of said groups R1-R5 is an integer from 1 to 12. The compounds wherein P has the formula (I) or (IA), as specified above, can be prepared through the reaction of a compound of the formula (II). wherein in the case of the preparation of a compound of the formula (I), each of R1, R2, R3, R4 and R5 is independently H, CnH2n + 2, OCnH2n + 1, or N02, wherein n is a integer from 1 to 8, provided that not all R1, R2, R3, R4 and R5 are H; or wherein in the case of the preparation of a compound of the formula (IA), each of R1, R2, R3, R4 and R5 is H, Br, Cl, F, CF3, CN, NC, -CO2CnH2n +? linear or branched and racemic or chiral, CnH2n + 1 linear or branched and racemic or chiral OC n H 2n + 1 linear or branched and racemic or chiral, OCH2CnF2n +, N02 or OH, where n is an integer from 1 to 12; with a compound of the formula [X] m- [S] n as those groups defined above. The compounds of the formula (II) can be prepared by means of standard organic reagents which are suitable for those skilled in the art. Preferred groups for R1, R2, R3, R4 and R5 include nitro, fluoro, trifluoromethyl, methoxy, or (R) or (S) sec-alkyl such as (R) or (S) sec-butyl (chiral) or ( R) or ((SS)] sec-octyl (chiral) or n-alkyl such as n-octyl, n-hexyl or n-butyl It is preferred that only one of R1, R2, R3, R4 and R5 is not H The groups R1, R2, R3, R4 and R5 may be conveniently chiral or racemic in the case of groups with asymmetric atoms.Other aspects of the invention will be apparent in the course of the following descriptions of the illustrative embodiments, which are given for the illustration of the invention and are not intended to limit the same.

EXAMPLES EXAMPLE 1 Covalently trichlorosilanes represented in Figure 2 containing different lengths of saturated hydrocarbon chains were covalently bound to glass surfaces by immersing the glass in a solution containing the silanes. The solution was 5% water, 94% of a 1mM solution of acetic acid and MeOH and 1% (vol / vol / vol) of silane. The resulting layers were hydrophobic, with contact angles in the range of 75-90 ° C. The alignment of a commercially available ambient temperature nematic liquid crystal (Merck E-63) containing a mixture of alkyl cyanobiphenyls and having the following transition temperatures of LC K-80 ° CN-84 ° CI in contact with the layers Chemosorbides of these silanes were investigated, and the orientation obtained was homeotropic (ie, perpendicular to the surface of the substrate). the liquid crystal mixture E7 from Merck was also used containing cyanobiphenyls-C5, C7 and substituted and cianotrifenilo -OC8-C5 substituted as any material, composition, etc., which may exhibit anisotropy, preferably liquid crystallinity.

EXAMPLE 2 Experiment 1 was repeated with the exception that the silanes studied were 4-aminobutiltrietoxi silane (or ABTE), N- (2-aminoethyl) -3-aminopropyltrimethoxysilane silane (or EDA), diethylenetriamine-trimethoxysilylpropyl (or DETA) and 3- aminopropyltrimethoxy silane (or APS). See Figure 3. The four silanes have a polar group -NH2 at the free end of the molecule. This group modified the hydrophilic character of the surface of the substrate after the binding of the molecule. EDA and DETA contain, in addition to the terminal amine group at the end, one or two additional amine groups as bridge groups linking the hydrocarbon chains. This allows the variation of the degree of the hydrophilic character and / or the resistance of the dipolar interactions. The four amine silanes were chemisorbed on glass surfaces coated with ITO, and a common sandwich cell was made using Merck's E-63 liquid crystal mixture. Both glass surfaces of the cell in contact with the LC presented chemoadsorbed layers of alignment. The cells were examined in a rotating stage microscope with a light so. The LC cell was placed between the crossed polarizers inside the microscope. Figure 4 shows the photographs of the textures displayed by E-63 under the crossed polarizers. In the top row of the photographs, the average LC director is at a 45 ° angle to the polarizer or analyzer, while in the bottom row of the photographs, the director is parallel to any of them. An acceptable flat alignment was observed for all the chemically absorbed layers.

EXAMPLE 3 The layers of APS, ABTE, EDA, and DETA were chemisorbed on a flat glass according to the procedure described above and cinnamoyl groups were provided thereon as the polymerizable group P according to (iii) above. The layers were directionally polymerized as previously described with UV light. In order to compare the alignment obtained in the directionally polymerized (DP) region with that in a non-polymerized region, a mask was used to directionally polymerize only part of the chemisorbed layer. A cell with a thickness of 10 μm was prepared with E-63 sandwiched between two surface treated, directionally bonded substrates. All observations were made between the crossed polarizers and the cell was mounted on the rotating stage of a polarization microscope. It was found that the LC molecules are extremely well aligned in a uniform planar configuration in the surface region of the invention while hardly any alignment was present in the non-polymerized regions, the demarcation line being very sharp. Figure 8 shows photographs of two positions of the sample, that is, when the LC director is at 45 ° or parallel to the polarizer / analyzer axis. The DP region is uniformly dark in the latter almost, while it is uniformly bright in the first case. The quality of the alignment was also good that even under great amplification few defects were observed in the surface region of the invention. The particular equipment used was a Nikon Optihot polarization microscope with a 100W white light source and a 12 V DC power supply, a Nikon photodiode, a Melles Griot amplifier (for the optical signal) and a Keithley digital multimeter receiver ( 199 System DMM) or an Olympus BH-2 polarization microscope with a 100W white light source, a 12 V DC power supply, a UDT photodiode, and a Model 5370 UDT optimeter with a development amplifier. Both teams used a wavetek model 395 synthesized arbitrary waveform generator and a 50/750 Trek amplifier to apply the electric field to the samples. In all cases, excellent contrast ratios were obtained with the surface of the invention.

EXAMPLE 4 Alignment surfaces were prepared according to Example 1 on glass surfaces coated with pure ITO. A cell was made with E-63 in a twisted nematic configuration, so that the LC was in direct contact on both sides with the DP treated substrates mounted so that the polymerization direction for the two substrates was orthogonal to each other. This resulted in a twisted nematic cell (TN) with good alignment, as seen in Figure 9. The Figure shows the cell between parallel polarizers and between crossed polarizers. Once again, the treated region of the invention gave a uniform flat alignment, while the untreated region showed no alignment. However, it was observed that the alignment quality in ITO, in general, was not as perfect as it was in flat glass. It is believed that this is due to the inherent inhomogeneities of the surface on the ITO surface.

EXAMPLE 5 A glass coated with ITO and overcoated with a SiO2 layer was studied in the same manner as in Example 1. These substrates are typical to those used by the visu-alization device industry. ITO glass (225 ohms / square surface resistance) coated with 690 A SiO2 (purchased from Donnely Corporation) was used. The passive ITO was subjected to treatment under exactly the same conditions as in Example 3 using APS with a cinnamoyl group. A sample cell with the directionally linked, treated and passivated ITO surfaces was prepared in a TN configuration. Excellent alignment was obtained in the surface regions of the invention (Figure 10). Actually, the aligned regions were free of defects even when they were observed with increased amplification energy. The contrast ratio was very high and comparable with that of the commercial TN cells of the same thickness. Although contrast ratios vary with the equipment used to measure them, ratios of > 9 and as high as approximately 33.

EXAMPLE 6 X-S-P molecules (n = m = o = 1) were chemised on aluminum oxide as in Example 1. Here P is acrylate, S is alkyl of 10 carbon atoms and X is carboxyl. Directional polymerization was carried out as in Example 3.

EXAMPLE 7 The molecules X-S-P (n = m = o = 1) were chemised on a gold surface by dissolving the molecules in solvent and applying the solution to the gold surface for 24 hours. Here X is a thiol group, S is a para-substituted bicyclohexyl group and P is a strenuous group. The directional polymerization was carried out as in Example 3. In this way, it has been shown that the entanglement • Directional results in surfaces that provide a uniform flat alignment on substrate surfaces including glass, passive ITO and ITO surfaces. Now electro-optical studies will be described in the two TN cells were made from passive ITO and ITO surfaces with alignment layers directionally intertwined.

• EXAMPLE 8 Two TN cells with a thickness of 10 microns were prepared with the alignment surfaces of the invention on pure ITO in one case and ITO passivated in the other case. The chemo-adsorbed material used was ABTE (pure ITO) or APS (ITO passivated) both with P-cinnamoyl groups. The electro-optical characteristics of the two cells are shown in Figures 12 and 13, respectively. In both cases, the surface treatment of the invention provided sufficient anchoring for the operation of a TN device. The ignition time for both cells is very fast (<0.5 ms) and comparable with commercial TN cells. The switch-off times were 16 ms for pure ITO (Figure 11) and 55 ms for passive ITO (Figure 12).

EXAMPLE 9 Synthesis of the Chromophores Figure 14 describes two reaction paths, which lead to 4-alkoxy cinnamic acid. The 4-hydroxy cinnamic acid (1) is reacted with an alkyl ide and an excess of potassium hydroxide to produce the corresponding racemic 4-alkoxy cinnamic acid (4a). This procedure is applicable for racemic alkyl ides. If a fluorinated alkoxy substitution is desired, fluorinated alkyl ides must be used. To obtain chiral 4-alkoxy cinnamic acids, the 4-hydroxy cinnamic acid (1) of Figure 14 is heated under reflux in methanol with catalytic amounts of acid to give 4-hydroxymethyl cinnamate (2) with a yield of 96%. Etherification of (2) with a chiral alcohol or chiral fluorinated alcohol via the Mitsunobu reaction in the presence of triphenylphosphine (TPP) and diethyl azodicarboxylate (DEAD) gave the 4-alkoxymethyl cinnamate (3) with a yield of 90 %. The Mitsunobu reaction proceeds with an inversion of the configuration at the chiral center. Deprotection of the acid function of (3) led to 4-alkoxy cinnamic acids (4a). The acid chloride form of the chromophores (5) required during the chemisorption process was obtained through the reaction of the substituted cinnamic acids (4) with an excess of thionyl chloride in benzene. The reaction mixture was refluxed overnight to give (5) in a 90% yield. A number of chromophores synthesized after the procedure given above is shown in Figure 15. Synthesis. 4-Hydroxy-methyl cyanamide (2): 0.09 mmol of 4-hydroxy cinnamic acid (1) was added to 200 ml of anhydrous methanol together with 2 ml of methanesulfonic acid. The reaction mixture was refluxed for 16 hours. The methanol was removed under vacuum in the rotary evaporator. The ester (2) was recrystallized from a mixture of absolute ethanol / hexane (70: 1) and was obtained in 50% yield. 4-alkoxymethyl cinnamate (3): 16.8 mmoles of (2), 16.8 mmoles of alkanol (chiral or racemic) and 17.16 g of triphenyl phosphine (TPP) were dissolved in 85 ml of anhydrous THF under a nitrogen atmosphere. Diethyl azodicarboxylate (DEAD) in 10 ml of anhydrous THF was added dropwise and the resulting mixture was stirred overnight at room temperature. 1 ml (DEAD) was added to quench the excess TPP. The solvent was evaporated and the residue was extracted with 4: 1 hexane / ethyl acetate. The solvent was removed under vacuum and the resulting crude product was purified through column chromatography using hexane / ethyl acetate 4: 1. The product (3) was obtained in a yield of 75%. 4-aikoxy-cinnamic acid (4): 11.4 mmoles of (3) were dissolved in a mixture of 150 ml of methanol and 40 ml of water. 50.8 mmol of lithium hydroxide monohydrate were added and the mixture was stirred overnight at room temperature. The solvent was removed and the residue was acidified with 1: 1 HCl / water. The product was collected by vacuum filtration and recrystallized from ethane acid a (4a) in 70% yield. Method 2: For the commercially available racemic alkyl bromides it is possible to go in a step from 4-hydroxy cinnamic acid (1) to 4-alkoxy cinnamic acid (4a). 1 mmol of (1) was dissolved in an ethanol / water mixture (75/25%), 3 mmol of KOH and catalytic amounts of Kl were added and the mixture was refluxed for 1 hour. After, 1 mmol of the alkyl bromide was added and the mixture was refluxed for 1 hour. Then, 1 mmol of the alkyl bromide was added and the reaction mixture was refluxed for 24 hours. The solvent was removed on the rotary evaporator and the precipitate was acidified with HCl. The product was recrystallized from a mixture of ethanol / water (75/25%). The yield of the reaction was 70%. Synthesis of cinnamoyl chlorides (5): 1 mmole of cinnamic acid (4) was dissolved in anhydrous benzene and stirred in a flask covered with an aluminum foil. 3 mmol of thionyl chloride were added and refluxed with stirring overnight. The solvent was removed under vacuum and the product (5) was recrystallized from hexane. The cinnamoyl chloride derivatives were obtained in a yield of 90%.

EXAMPLE 10 Additional Synthesis of Nitro- and Methoxy-Substituted Cinamoyl Chlorides The course of the reaction is given in Figure 14. 25.8 mmoles of nitro- and methoxy-substituted cinnamic acid were dissolved in 100 ml of anhydrous THF and stirred at room temperature under a nitrogen atmosphere in a flask covered with a aluminum. Oxalyl chloride (51.6 mmol) was added dropwise in 30 minutes. The reaction mixture was stirred overnight. The solvent was removed under vacuum. To remove excess oxalyl chloride, anhydrous hexane (three times, 100 ml) was added and the solvent was evaporated on a rotary evaporator. The cinnamoyl chloride derivatives were obtained in a yield of 95%.

EXAMPLE 11 Additional Synthesis of Alkoxy-Cinamoyl Chlorides (for a substitution at position 4) The reaction path is shown in Figure 15. 4-hydroxymethyl cinnamate (2): 0.09 mmoles of 4-hydroxy cinnamic acid (1) were added to 200 ml of anhydrous methanol together with 2 ml of methanesulfonic acid . The reaction mixture was refluxed for 16 hours. The methanol was added under vacuum in a rotary evaporator. The ester (2) was recrystallized from a mixture of absolute ethanol / hexane (70: 1) and obtained in a yield of 50%. 4-Alkoxy-methyl (3) cinnamate: 16.8 mmoles were dissolved (2), 16.8 mmol of alkanol (chiral or racemic) and 17.6 g of triphenylphosphine (TPP) in 85 ml of anhydrous THF under a nitrogen atmosphere. Diethyl azodicarboxylate (DEAD) in 10 ml of anhydrous THF was added dropwise, and the resulting mixture was stirred overnight at room temperature, and 1 ml of DEAD was added to quench the excess of TPP. The solvent was evaporated, and the residue was extracted with 4: 1 hexane / ethyl acetate. The solvent was removed under vacuum and the resulting crude product was purified through column chromatography using hexane / ethyl acetate 4: 1. The product (3) was obtained in a yield of 75%. 4-alkoxy cinnamic acid (4): 11.4 mmoles of (3) were dissolved in a mixture of 150 ml of methanol and 40 ml of water. 50.8 mmol of lithium hydroxide monohydrate was added, and the mixture was stirred overnight at room temperature. The solvent was removed, and the residue was acidified with 1: 1 HCl / water. The product was collected by vacuum filtration and recrystallized from acid ethanol to give (4) in 70% yield. 4-alkoxy-cinnamoyl chloride (5): 6.2 mmoles of (4) were dissolved under nitrogen and stirred in 30 ml of anhydrous THF in a flask covered with an aluminum foil. 18.6 mmol of oxalyl chloride were added, and the mixture was stirred overnight. The solvent was removed under vacuum. To remove excess oxalyl chloride, anhydrous hexane (three times 100 ml) was added, and the solvent was evaporated on a rotary evaporator. The cinnamoyl chloride derivatives were obtained in a yield of 95%.

EXAMPLE 12 Synthesis of Molecules Containing a Directionally Interlatable Portion As shown in Figure 16, a substituted cinnamoyl chloride can be connected to the silane portion prior to the chemoadsorption process. To a mixture of 1 mmole of 3-amino-propyl-trimethoxy-silane (6) and 1 mmole of triethylamine in THF at 0 ° C was added dropwise a solution of 1 mmole of substituted cinnamoyl chloride (5) in THF The reaction mixture was stirred and allowed to warm to room temperature. After 3 hours, the mixture was filtered and the solvent was evaporated and methylene chloride was added. The solution was washed with cold water and dried over MgSO4. The solvent was evaporated and the mixture was filtered on a short column with ethyl acetate / hexane (2/3) as an eluent, after evaporation of the solvent the product (6a) was dried under vacuum. The yield was 80%.

EXAMPLE 13 Chemisorption and Modification of the Chemisorbed Layer The reaction solution was prepared as follows: 94% (by volume) of a 1 mM solution of acetic acid in methanol (HPLC grade) were combined with 1 aminosilane 6 or trimethoxysilane 6_a and 5% distilled water # 18OW (vol. vol / vol). Freshly cleaned substrates (wet cleaning or plasma chemical etching) were treated for 15 minutes with the amino silane solution at room temperature. The substrates were rinsed once with methanol (HPLC grade), dried and baked for 5 minutes at 110 ° C. Formation of the amine: After cooling, the aminosilane substrates were rinsed twice with acetonitrile and then treated with a substituted cinnamoyl chloride solution as prepared in Examples 9 and 10 (60mM) and diisopropylethylamine ( 30mM) in anhydrous acetonitrile under the exclusion of light. (This step is not necessary if trimethoxysilane 6a was used for chemoadsorption).

EXAMPLE 14 In order to demonstrate the applicability of the present alignment procedure to liquid crystal display devices, both flat and twisted nematic cells were manufactured. Electro-optical characteristics were recorded to show that the alignment procedure is applicable to these devices. Although the examples discussed below refer only to flat and TN cells, the method is certainly applicable to, but not restricted to, monochromatic displays as well as color TN, used in both active and passive directed modes, active matrix displays, thin film transistor (TFT), super-twisted compensated film (STN) nematic screens. Subtractive color STN displays, devices directed by laser A- • 10 smectic, ferroelectric LCDS, electroclinic LCDS, light valve devices and projection mode. Some examples of specific devices are discussed later. Preparation of flat cells. Flat cells with a thickness of 20 μm were fabricated with pure ITO substrates treated with substituted DPS 15. Before assembling the cell, epoxy glue was applied parallel to the edges on a substrate. The second substrate is • placed on the first with the surfaces treated with DPS looking at each other and with the preferred alignment direction of the upper substrate parallel to that of the lower substrate. Approximately 20 μm cell thickness was obtained with glass spheres. The glue was cured at 65 ° C for 4 hours under vacuum. The capillary cell was filled with the E7 liquid crystal mixture in the isotropic phase. These cells were used for pre-tilt measurements. 25 Preparation of twisted nematic cells (TN). TN cells with a thickness of 5 mm were fabricated with pure ITO substrates treated with substituted DPS. Epoxy glue was applied parallel to the edges on a substrate. The second substrate was placed on the first with the surfaces treated with DPS facing each other and with the preferred alignment direction of the substrate greater than 90 ° C with respect to that of the lower substrate. The substrates were displaced to approximately 5 mm to allow subsequent electrical contacts. An approximate cell thickness of 20 μm was obtained with glass spheres. The glue was cured at 65 ° C for 4 hours under vacuum. The cell was filled capillary with the E7 liquid crystal mixture in the isotropic phase. These cells were used for electro-optical studies.

EXAMPLE 14a Parallel Liquid Crystal Cell of 4-Nitro-Substituted DPS The cell showed good alignment between crossed polarizers under a microscope. It was found that the contrast ratio is 30.

EXAMPLE 14b Parallel Liquid Crystal Cell of 3-Nitro-Substituted DPS The cell showed good alignment between crossed polarizers under a microscope. It was found that the contrast ratio is 30.

EXAMPLE 14c Parallel Liquid Crystal Cell of DPS 4-Metoxy-Su bitumen The cell showed good alignment between crossed polarizers under a microscope. It was found that the contrast ratio is 30.

EXAMPLE 14d Parallel Liquid Crystal Cell of 4-Butoxy-Substituted DPS The cell showed good alignment between crossed polarizers under a microscope. It was found that the contrast ratio is 30.

EXAMPLE 15 Determination of the Pre-tilt through the Crystal Rotation Method Crystal Rotation Method The glass rotation method was used to determine the pre-tilt angle in flat cells. It was assumed that the angle of pre-tilt that the optical axis makes with the surface in small (0-10 degrees).

The method is based on the determination of the optical phase delay and the intensity transmitted as a function of the angle of incidence of the laser beam with respect to the normal cell walls. The same cell is rotated about an axis perpendicular to the optical axis. The transmitted intensity that oscillates the angle of incidence is charged. The intensity curve is symmetric around a certain angle called the point of symmetry, which is related to the pre-tilt angle. In this way, if ordinary and extraordinary refractive indices and cell thicknesses are known, the pre-tilt angle can be calculated. The accuracy of the method is of the order of 0.3 degrees. Figure 16 shows an outline of the experimental representation.

EXAMPLE 15a Pre-tilt over the Cell with 4-Nitro-Substituted DPS The pre-tilt was measured and was 2 ° (Figure 18).

EXAMPLE 15b Pre-tilt over Cell with 3-Nitro-Substituted DPS The pre-tilt was measured and was 1.5 ° (Figure 19).

EXAMPLE 15c Pre-tilt over the Cell with 4-Methoxy-Substituted DPS The pre-tilt was measured and was 0.1 ° (Figure 20).

EXAMPLE 15d Pre-tilt over Cell with 3-Butoxy-Substituted DPS The pre-tilt was measured and was 0.25 ° (Figure 21).

EXAMPLE 15e Pre-tilt over the Cell with 100% 4-Nitro-Substituted Chromophore The pre-tilt was measured and was 16 ° (Figure 22).

EXAMPLE 15f Pre-tilt on the Cell with 50% 4-Nitro-Substituted Chromophore and 50% Unsubstituted (Figure 23) The pre-tilt was measured and it was 201 EXAMPLE 15g Pre-tilt Dependence on Chromophore Polarity for E7 Liquid Crystal Blend The results are established in Table 1 of Figure 24.

EXAMPLE 15h Dependence of the Pre-tilt on the Polarity of the Chromophore for Liquid Crystal Mix ZL1 4792 The results are established in Table 2 of Figure 25.

EXAMPLE 15i Dependence of the Pre-tilt on the Chromophore Polarity for the Liquid Crystal Mix ZL1 4792 and E7 The results are established in Table 3 of Figure 26 and Figure 27.

EXAMPLE 15 Pre-inclinations of Alignment Layers with Fluorinated Substitution The results are set forth in Table 4 of Figure 2 In this manner, the inventors of the present invention have demonstrated that the anisotropic alignment surfaces of the invention produce uniform or flat inclined or non-inclined homeotropic alignment of compounds on substrates. The preferred method of the invention is a very simple and effective method for different substrate surfaces. Also, the alignment layer is stable to heat and light, can be colorless, provides excellent contrast, few or no blemishes, can be made very thin and can be chemically bonded to the substrate. The process of the present has several important aspects: it is a simple procedure greatly at room temperature, which is easy to amplify for manufacturing, in a preferred embodiment produces a chemically linked alignment layer ensuring long-term stability, and is applicable to substrates used in twisted magnetic devices, super-twisted nematic devices, active matrix devices, etc. The alignment surfaces of the invention are useful in all optical recording media and devices and, in particular, in liquid crystal (LCD) devices, which require alignment substrates. These devices include screens, spatial light modulators, phase shift devices, nonlinear optical devices, twisted nematic devices, super-twisted nematic devices, double super stiched nematic devices, triple layer nematic devices, active matrix displays, multiplexed of the aforementioned devices, flat switching devices (IPS), vertical alignment screens, surface stabilized ferroelectric liquid crystal displays (SSFLCD), electroclinical screens, etc. Of course, flat panel screens, TV screens, computer screens, etc. are included. These devices are well known in the art, and several of these devices are deciphered in Handbook of Display Technology, Castilian J. A. Academic Press, Inc., 1992, incorporated herein by reference. Chapter 8 of this publication is particularly useful. The worker can provide the LC devices listed above in accordance with the present invention simply by substituting the surface alignment layer described herein for the alignment layer (s) n used in prior art devices. The inclination angles provided by the surfaces of the invention vary from OEa 90E, and preferably of more than zero to 15 °, including 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15 °. You can also provide inclinations of 20 °, 30 °, 40 °, 45 °, 50 °, 60 °, 70 °, 80 °, and 85 °, as well as all the values and scales between them. In devices that require patterned viewing areas, etc., the above surfaces can be directionally linked through a mask, etc., to provide only certain areas with the alignment surface of the invention, or compounds of the invention can be applied. Formula 1 only to certain areas of a substrate. In addition, a mask can be used to directionally link certain areas using, for example, polarized UV light, polarized in a first direction followed by directional entanglement of other areas of the same substrate with, for example, polarized UV light, which is polarized in a second direction. You can make pixels of multiple domains in this way, etc. Of course, mixtures of compounds of the formula 1 can be used on a single substrate, and substrates with domains of different compounds of the formula 1 can be used. Colored substrates can be used, as well as compounds of the color formula 1, fluorescent, etc., made by its chemical constitution. Additives such as colorants, etc. can be added to the layers of the invention before or after the directional binding. The liquid crystal materials oriented by the surfaces of the invention are not particularly limited and include those exhibiting nematic, cholesteric, smectic, discotic, etc. phases, including ferroelectric materials (particularly those with substitution of side fluorine). The liquid crystals can be used individually or in a mixture, including eutectic mixtures. Superfluous nematic mixtures can be used. Compositions of two or more liquid crystals are preferred. Examples of liquid crystals and their mixtures are described in Liquid Crystals in Tabellen, Vols. I and II, incorporated herein by reference, and in E.U.A. 5,032,009, incorporated herein by reference, etc. Guest-host compositions are also included, wherein mixtures of liquid crystals are provided with, for example, colorants, non-linear optical compounds, etc. In particularly preferred embodiments of the present invention, the alignment surface is chiral, since the molecules of formula 1 are chiral, the PP 'bond is chiral, X is chiral, P is chiral, S is chiral, and combinations of these are , etc. Chirality of shape and geometry is included. Obviously, numerous modifications and variations of the present invention are possible, in light of the above teachings. Therefore, it should be understood that, within the scope of the claims hereof, the invention may be practiced in a manner different from that specifically described herein.

Claims (31)

1. - A substrate having on at least a portion of a surface thereof a directionally linked, anisotropic, chemisorbed layer, comprising a compound of the formula: [Xm] - [S] "- [P] o 1 wherein: X is a chemical functional group capable of chemisorption to said substrate, S is a separator separating X and P, and P is a directionally linkable group, and n, my or all are integers greater than or equal to 1, wherein m > _ n y o > _ n, where P has the formula (I): wherein each of R1, R2, R3, R4 and R5 is independently H, linear or branched H, CnH2n + 1, linear or branched OC n H 2n + 1, or NO 2, wherein n is an integer from 1 to 8, and wherein at least one of R1, R2, R3, R4 and R5 is not H.

2. A substrate having on at least a portion of a surface thereof a directionally linked, anisotropic, chemisorbed layer, comprising a compound of the formula: where: X is a chemical functional group capable of chemisorption to said substrate, S is a separator separating X and P, and P is a directionally linkable group, and m and y of the formula [X] m- [S] n- [ P] 0 are all integers greater than or equal to 1, n of formula 1 is zero, or an integer greater than or equal to 1, where m ^ ny ^ n, and where P has the following formula (IA): wherein each of R, R2, R3, R4 and R5 is H, Br, Cl, F, CF3, CN, CN, -C02CnH2n + 1 linear or branched and racemic or chiral, CnH2p + 1 linear or branched or racemic or chiral, linear or branched or racemic or chiral OCnH2n + 1, OCH2CnF2n +?, NO2 or OH, wherein n of said groups R1-R5 is an integer from 1 to 12.

3. The substrate according to claim 1 or 2, wherein the chemically absorbed layer comprises two or more compounds of the formula [X] m- [S] n- [P] 0.

4. The substrate according to claim 1 or 2, wherein the chemisorbed layer does not absorb light in the scale of visible wavelength.

5. The substrate according to claim 1 or 2, wherein the chemisorbed layer absorbs light in the scale of visible wavelength.

6. The substrate according to claim 1 or 2, wherein the chemisorbed layer is formed in a pattern.

7. The substrate according to claim 1 or 2, wherein the chemisorbed layer is capable of homeotropically aligning liquid crystalline molecules in contact therewith.

8. The substrate according to claim 1, wherein the chemically absorbed layer is capable of aligning liquid crystalline molecules in contact therewith in a uniaxial planar orientation, said liquid crystalline molecules being optionally inclined from 3 to 85 ° with respect to the surface of the substrate.

9. The substrate according to claim 1 or 2, wherein the chemisorbed layer is capable of aligning liquid crystalline molecules in contact therewith in a uniaxial planar orientation, said liquid crystalline molecules being optionally inclined from 0 to 90 ° with with respect to the surface of the substrate.

10. A liquid crystal device comprising the substrate of claim 1 or 2.

11. A liquid crystal display device comprising the substrate of claim 1 or 2.

12. The substrate according to claim 1 or 2, wherein said substrate is selected from the group consisting of S02 glass, Si02 glass coated with ITO, polysilicon, metal, glass coated with plastic ITO with a passivation layer containing SiO2 on top or bottom of the ITO layer, boron silicate coated with ITO, boron silicate coated with ITO with a passivation layer containing SiO2 on the top or bottom of the ITO layer, ITO-coated plastic and ITO-coated plastic with a layer of passivation containing SiO2 on top or bottom of the ITO layer.

13. The substrate according to claim 1 or 2, wherein said substrate comprises a pixel of a domain, two domains or multiple domains having a first compound, [X] m- [S] n- [P ] 0 in a first portion of said pixel and a second compound [X] m- [S] n- [P] 0 in a second portion of said pixel.

14. The substrate according to claim 1 or 2, wherein the substrate comprises a pixel of a domain, two domains or multiple domains having the same compound [X] m- [S] n- [P] 0

15. - A phase modulator comprising the substrate of claim 1 or 2. 16.- A non-linear optical device comprising the substrate of claim 1 or 2. 17.- A spatial light modulator comprising the substrate of the claim 1 or 2. 18. A method for preparing the substrate of claim 1 or 2, comprising the steps of chemisorbing a compound of formula 1 on at least a portion of a surface of a substrate, followed by directional binding. 19. The method according to claim 18, wherein the directional link is achieved with light radiation. 20. The method according to claim 18, wherein the directional linkage comprises the treatment with circular or elliptically polarized UV light. 21. The method according to claim 18, wherein the directional binding comprises the treatment with linearly polarized UV light. 22. The method according to claim 18, wherein the directional linkage comprises the treatment with linear, circular or elliptically polarized UV light and a pre-tilt is provided by a single exposure or multiple exposure at normal incidence. 23. The method according to claim 18, wherein the directional linkage comprises the treatment with linear, circular or elliptically polarized UV light and a pre-tilt is provided by a single exposure or multiple exposure to oblique incidence. 24. The method according to claim 18, wherein the directional linkage comprises the treatment with linear, circular or elliptically polarized UV light and a pre-tilt is provided by a multiple exposure and a combination of normal and oblique incidence. 25. The method according to claim 18, wherein the directional linkage comprises the treatment with linear, circular or elliptically polarized UV light and a pre-tilt is provided by a single exposure or multiple exposure to a normal or oblique incidence or a combination thereof with a variation of the polarization state during different exposures. 26. The substrate according to claim 1, wherein m = n = o = 1. 27.- A compound of formula 1: [Xjm- [S] n- [P] 0 1 where: X is a chemical functional group capable of adsorption, absorption or chemisorption to a surface or a substrate, S is a group separator, and P is a directionally linkable group of the formula (I): wherein each of R1, R2, R3, R4 and R5 is independently H, CnH2n + 1 linear or branched, OCnH2n +. linear or branched, or NO2, where n of said groups R1-R5 is an integer from 1 to 8, provided that not all of R1, R2, R3, R4 and R5 are H, and n, m, I of the formula 1 are all integers greater than or equal to 1, and m > n of formula 1 and o > n of formula 1; or P is a directionally linkable group of the following formula (IA): (IA) wherein each of R1, R2, R3, R4 and R5 is H, Br, Cl, F, CF3, CN, CN, -CO2CnH2n + 1 linear or branched and racemic or chiral, CnH2n +. linear or branched or racemic or chiral, OCnH2n +? linear or branched or racemic or chiral, OCH2CnF2n + 1, N02 or OH, wherein n of said groups R1-R5 is an integer from 1 to 12, and m and y of formula 1 are each integers greater than or equal to 1, and n of formula 1 is either 0 or an integer greater than or equal to 1, and m of formula 1 > _ n of formula 1 and o of formula 1 > of formula 1. 28.- A compound according to claim 27, wherein X is a group of the formula -Si (OH) 3, -SiR2OH, or SiR3, wherein R is an alkoxy group of 1 to 10 carbon atoms and S is an individual bond; an alkylene group of 1 to 30 linear carbon atoms; an alkylene group having from 2 to 30 linear carbon atoms interrupted by one or more aromatic groups, peptide groups, heterocyclic groups, NH, NR, wherein R is a hydrocarbon group of 1 to 18 carbon atoms, O, S, COO, SOn, where n is 1-4, CO, phosphorus, phosphine, phosphate or phosphite groups; an alkylene group of 3 to 30 carbon atoms branched; or, an alkylene group of 3 to 30 branched carbon atoms interrupted by one or more aromatic groups, peptide groups, heterocyclic groups, NH, NR, wherein R is a hydrocarbon group of 1 to 18 carbon atoms, O, S, COO, SOn, where n is 1-4, CO, phosphorus, phosphine, phosphate, or phosphite groups. 29. A compound according to claim 27, wherein X is a group of the formula -Si (OH) 3, -SiR2OH, or SiR3, SiCl3, SiRCI2, Si (R) 2CI, wherein R is a group alkyl of 1 to 10 carbon atoms or an alkoxy group of 1 to 10 carbon atoms, and S is an individual bond; an alkylene group of 1 to 30 linear carbon atoms; an alkylene group having from 2 to 30 linear carbon atoms interrupted by one or more aromatic groups, peptide groups, heterocyclic groups, NH, NR, wherein R is a hydrocarbon group of 1 to 18 carbon atoms, O, S, COO, SOn, where n is 1-4, CO, phosphorus, phosphine, phosphate or phosphite groups; an alkylene group of 3 to 30 carbon atoms branched; or an alkylene group of 3 to 30 branched carbon atoms interrupted by one or more aromatic groups, peptide groups, heterocyclic groups, NH, NR, wherein R is a hydrocarbon group of 1 to 18 carbon atoms, O, S, COO , SOn, where n is 1-4, CO, phosphorus, phosphine, phosphate, or phosphite groups. 30. A compound of the formula (II): (II) wherein each of R1, R2, R3, R4 and R5 is independently H, CnH2n +? linear or branched, OCnH2n +?, or N02, where n is an integer from 1 to 8, provided that not all of R1, R2, R3, R4 and R5 are H. 31.- A compound of the formula (NA) : wherein each of R1, R2, R3, R4 and R5 is H, Br, Cl, F, CF3, CN, CN, -C02CnH2n + linear or branched and racemic or chiral, CnH2n + 1 linear or branched and racemic or chiral , Linear or branched and racemic or chiral OC n H 2n + 1, OCH 2 CN n F 2 n + 1, NO 2 or OH, wherein n of said groups R 1 -R 5 is an integer from 1 to 12.