JP2012523589A - Composition for LCD alignment layer - Google Patents

Abstract

The present invention relates to a composition for use in a surface-director alignment layer disposed between a confinement substrate of a liquid crystal device and a liquid crystal bulk material. And
The surface-director alignment layer causes liquid crystal molecules contained in the liquid crystal bulk material to form a desired pretilt angle with respect to the surface-director alignment layer when there is no applied electric field, and the composition has the following: When used alone in the surface-director alignment layer, a first concentration of the first compound that produces a first pretilt angle Θ ₁ different from the desired tilt angle; and alone in the surface-director alignment layer A second mixture of a second concentration that produces a second pretilt angle Θ ₂ that is different from the desired tilt angle and the first pretilt angle, whereby the desired tilt angle The pretilt angle relates to a composition that can be controlled by controlling at least one of the first and second concentrations. The composition of the present invention provides a controllable pretilt angle of the liquid crystal that is continuously controllable over the entire concentration of the first and second compounds, improving the reproducibility of the alignment layer manufacture.
[Selection] Figure 2

Description

  The present invention relates to a polymer composition comprising a mixture of at least a first compound and a second compound for use in a surface director alignment layer, and a liquid crystal device utilizing such a surface director alignment layer.

A liquid crystal device generally includes a liquid crystal material layer disposed on a substrate or disposed between a pair of substrates.
Liquid crystal molecules are typically relatively hard molecules that exhibit shape anisotropy and have the ability to align along the long axis in some desired direction. The average direction of the molecule is specified by the vector quantity and is called a director.
In liquid crystal displays (LCDs), in the absence of an external field such as an electric field, the desired initial orientation of the liquid crystal layer is generally the so-called orientation layer (orientation) on the confined substrate surface facing the liquid crystal bulk. It can be achieved by a suitable surface treatment of the surface of the confined solid substrate, such as applying an orienton layer. The initial liquid crystal alignment is defined by the solid surface / liquid crystal interaction at the contact surface between the liquid crystal layer and the alignment layer.
The orientation (orientation) of the liquid crystal molecules adjacent to the confining surface is transferred to the liquid crystal molecules in the bulk via elastic forces, thus essentially giving all liquid crystal bulk molecules the same orientation.

A director of liquid crystal molecules close to the contact surface between the liquid crystal layer and the alignment layer (herein also referred to as a surface director) is, for example, perpendicular to the confined substrate surface (VA, also referred to as homeotropic or vertical alignment, VA) Strong to point in a certain direction, such as horizontal to the confinement substrate surface (also referred to as planar orientation, PA) or a certain predetermined tilt angle (also referred to as pretilt angle) towards the confinement substrate surface It is done. The type of alignment in a liquid crystal display depends on the application required for the device.
Known methods for constructing the alignment layer are, for example, organic film rubbing and inorganic film vapor deposition.
According to the organic film rubbing method, for example, an organic coating of polyimide is formed on the substrate surface. The organic coating is then rubbed in a predetermined direction using, for example, a cotton, nylon or polyester cloth so that the liquid crystal molecules in contact with the layer are oriented in the rubbed direction. Organic film rubbing can be used to perform planar alignment of liquid crystal molecules.

In the inorganic film deposition method, the inorganic film is formed on the substrate surface by vapor deposition of an inorganic substrate such as silicon oxide at an angle to the confinement substrate, whereby the liquid crystal molecules depend on the inorganic material and the evaporation conditions. , Oriented by an inorganic film in a specific direction. Due to the high production costs, the method is not suitable for large scale production, so this method is not used in practice.
In particular, the vapor deposition method can be used for certain special purposes, such as a Liquid-Crystal-on-Silicon (LOCS) microdisplay with a very small active display area. Vapor deposition is typically used to achieve planar alignment (PA) or tilt alignment (TA) of the liquid crystal.
Planar alignment (PA) is one of the two main types of liquid crystal alignment used in LCDs. Today, the most widely used method for obtaining PA is the organic film rubbing method. This method is also employed to obtain TA with a small pretilt over a large area by using a suitable polymer material for the preparation of the alignment layer.

  Vertical (homeotropic) alignment (VA) is the other of the main types of liquid crystal alignment. This type of orientation is usually performed by polymer oriented films that exhibit low surface energy. The VA of the liquid crystal is also realized by covering the surface of the solid substrate in contact with the liquid crystal with a surfactant. This method, however, is rarely used due to its complexity and very low level of reproducibility. Therefore it is not suitable for practical purposes. The PAs utilized in LCDs are in fact TAs that always have a small (some) or moderate (about 10 °) pretilt. Large pretilts of about 45 ° or greater are used in some optical devices such as bistable nematic LCDs and liquid crystal light modulators (LCLMs) and electrically controlled optical phase plates (ECORs). Very important to. A large pretilt in bistable nematic LCDs is essential to allow a transition between two bistable states induced by an applied electric field (GD Boyd, J. Cheng, P. Ngo, Appl. Phys. Lett, 36, 556-558, 1980; H. Kwok. F. Yeung, Y. Li, SID06Digest, 1622-1625, 2006). A large pretilt in the optical element is required for high-speed switching (A. Golovin, S. Shiyanovskii, O. Lavrentovich, Appl. Phys Lett, 83, 3864-3866, 2003).

Thus, in some cases, it may be desirable for the alignment layer to promote a predetermined tilt angle, also known as a pretilt angle, of the director toward the substrate. Such a pretilt angle may, for example, reduce the response time of the liquid crystal material when applying an electric field and / or promote more uniform reorientation of the liquid crystal molecules. In general, the larger the pretilt angle, the better the performance of the liquid crystal material. Ideally, the pretilt angle should be 45 °. However, large pretilt angles have proven difficult to create.
Currently, several methods are known for obtaining tilt alignment (tilt alignment), but only a few of these methods provide continuous control of the pretilt angle Θ in the range of 0 ° -90 °. It is possible. One method that allows continuous control of pretilt angles from 0 to 90 ° is described in H.W. Proposed by Kwok et al. (Journal of the SID, 16, 911-918, 2008). According to Kwok et al., The alignment layer is made from a composition of two alignment materials that are polyimide and not mixed. Each of these two materials promotes PA or VA, respectively, and in the composition of the alignment layer, they are separated into nano-sized regions, usually about a few hundred nanometers in size. By changing the ratio of the concentrations of the two materials in the alignment layer composition, the pretilt angle can be continuously controlled in the range of 0 ° -90 °.

  A second method for continuous control of 0 ° to 90 ° pretilt is described in P.C. Proposed by Bos et al. (Liquid Crystals 33, 1191-1197, 2008). According to this method, which is a modification of the method of Kwok et al., The alignment film is a sandwich of two alignment layers made of polyimide. The first layer is deposited on a glass substrate, which has a continuous structure. A second layer is deposited on top of this layer. Since the material of the second layer does not wet the first layer sufficiently, the second layer has, for example, a domain-like discontinuous structure. Each of these layers promotes PA or VA, respectively. In conclusion, the contact surface of the double alignment layer with the liquid crystal has a non-uniform structure including a region promoting PA and a region promoting VA. The pretilt angle according to this method is controlled by the discontinuity of the second layer, in particular by the concentration of the material of the second layer.

However, layer separation and dewetting of two different compounds is a very difficult process to control and reproduce, and several external factors such as humidity can strongly influence these processes. Then, it will affect the amount of pretilt. It should also be noted that the nature of the alignment layer produced according to these two methods appears to be sensitive with respect to the thickness of the alignment layer (due to surface relief in LCDs with thin film transistors [TFT]). There is a change in the thickness of the alignment layer.) Therefore, both the domain separation method and the double alignment layer method, and furthermore they are time consuming methods, are not suitable for use in the LCD industry. Furthermore, the manufacture of alignment layers according to these two methods requires high temperatures and is therefore not suitable for use in the production of LCDs with plastic substrates.

G. D. Boyd, J.M. Cheng, P.A. Ngo, Appl. Phys. Lett, 36, 556-558, 1980 H. Kwok. F. Yeung, Y. et al. Li, SID06Digest, 1622-1625, 2006 A. Golovin, S.M. Shiyanovskii, O .; Lavrentovich, Appl. Phys Lett, 83, 3864-3866, 2003 H. Kwok et al. , Journal of the SID, 16, 911-918, 2008. P. Bos et al. , Liquid Crystals 33, 1191-1197, 2008

  One object of the present invention is to provide a surface director alignment material that can be easily changed to at least partially overcome the problems of the prior art and to obtain the desired pretilt angle of the surface director of the liquid crystal material. is there.

The present invention has discovered that this and other objects can be achieved by utilizing the compositions of the present invention. The present invention has pioneered a new field of technology: a controllable pretilt of liquid crystals by mixing miscible components containing different pretilts.
Therefore, in a first aspect, the present invention is a composition for use in a surface-director alignment layer disposed between a confinement substrate of a liquid crystal device and a liquid crystal bulk material comprising:
The surface-director alignment layer causes liquid crystal molecules contained in the liquid crystal bulk material to form a desired pretilt angle with respect to the surface-director alignment layer in the absence of an applied electric field.
A first concentration of a first compound which, when used alone in the surface-director alignment layer, produces a first pretilt angle Θ ₁ different from the desired tilt angle; and the surface-director alignment layer When used alone in a second concentration of a second compound that produces a second pretilt angle Θ ₂ different from the desired tilt angle and the first pretilt angle;
A uniform mixture containing
Here, the desired pretilt angle relates to a composition that can be controlled by controlling at least one of the first and second concentrations.

The composition of the present invention provides a controllable pretilt angle of the liquid crystal that is continuously controllable for all concentrations of the first and second compounds. The composition of the present invention promotes the alignment of the bulk liquid crystal basically through the steric interaction between each of the first and second compounds and the liquid crystal bulk molecules. Each of the first and second compounds, each of the following relationships with respect to the pre-tilt angle theta _e facilitated by the composition: Θ ₁ <Θ _e <Θ having _2, a liquid crystal bulk with pretilt theta ₁ and theta ₂ Promotes molecular orientation. The uniform dispersion of the components in the composition, and its orientation in the bulk liquid crystal via steric interaction between the liquid crystal molecules and the first and second components is the concept of orientation proposed in the present invention, The two most important differences between the above prior art methods in which the components of the alignment layer phase separate, form separation domains, and the liquid crystal alignment is controlled via the surface energy of these components. is there. The uniform dispersion of the polymer composition and the steric interaction between the first and second components and the liquid crystal bulk is easier to control and reproduce than the non-uniform dispersion of the components of the prior art alignment layer. is there.

Typically, the first pretilt angle may be smaller than the desired tilt angle, and the second pretilt angle may be larger than the desired tilt angle. The desired tilt angle can thus be controlled between the first pretilt angle and the second pretilt angle.
The first pretilt angle may preferably be in the range of 0 ° to 45 °, for example 5 to 25 ° with respect to the plane of the alignment layer, and the second pretilt angle is in the plane of the alignment layer. In contrast, it is in the range of 45 ° to 90 °, for example 70 ° to 85 °. In general, as the first or second pretilt angle deviates from 0 ° or 90 °, respectively, the desired pretilt angle of the liquid crystal bulk molecules becomes more controllable. However, it may be sufficient for one of the first or second pretilt angles to deviate clearly from 0 ° or 90 °, respectively, to achieve acceptable control. Thus, it may be preferred that the first pretilt angle is substantially 0 ° or the second pretilt angle is substantially 90 °. Otherwise, in an embodiment of the invention, the first pretilt angle is substantially 0 ° and the second pretilt angle is substantially 90 °.
Furthermore, at least one of the first and second compounds, preferably the second compound, can produce the pretilt angle by steric interaction.

In the aspect of the present invention, the first compound may include a first side group, and the second compound may include a second side group different from the first side chain group. At least one of the first and second side groups preferably exhibits shape anisotropy. For example, the first side group can be bound to a first repeat unit of the polymer backbone, and the second side group can be bound to a second repeat unit of the polymer backbone. The first and second repeating units may be exactly the same repeating units as the polymer backbone. Thus, by including the first and second compounds as repeat units in the same polymer, their miscibility can be ensured when the polymerization is carried out from a solution of monomers. Otherwise, the first and second repeat units may be repeat units with different polymer backbones.
The first side group can be bonded to the first repeating unit on the side surface. The second side group can be bound to the second repeating unit at the terminal end.

In an embodiment of the present invention, at least one of the first and second side groups may be linear. Furthermore, at least one of the first and second side groups may be an aromatic group. Similarly, at least one of the first and second side groups may be a mesogenic group.
Further, at least one of the first compound and the second compound includes a repeating unit functionalized with a pendant side chain selected from the group consisting of an optionally substituted alkyl group, an aryl group, and an alkylaryl group. obtain. In particular, at least one of said first and second compounds may comprise reactive, preferably photo-reactive side groups and / or photo-responsive side groups.

  Furthermore, in a second aspect, the present invention relates to a surface director alignment layer material comprising a composition as described above and an optional additional polymer. Advantageously, as a result of the composition of the present invention being a homogeneous mixture, the alignment layer becomes uniform, thereby avoiding many of the disadvantages of the prior art. For example, since the formation on the nano-domain is avoided, the influence of the layer thickness on the performance of the alignment layer is reduced. Thus, the properties of the alignment layer comprising the composition according to the invention are less sensitive to processing parameters such as humidity, temperature and deposition techniques. Similarly, the reproducibility of the alignment properties of the alignment layer according to the invention is very high compared to that of the alignment layer produced according to the prior art method.

In a third aspect, the present invention provides at least one confinement substrate, a liquid crystal bulk material, and a surface director alignment layer disposed between the at least one confinement substrate and the liquid crystal bulk material in contact with the surface of the liquid crystal bulk material. The surface director alignment layer as described above, that is, the liquid crystal device including the composition as described above. In particular, liquid crystal devices
-First and second confinement substrates sandwiching the liquid crystal bulk material;
A first surface director alignment layer disposed between the first confinement substrate and the liquid crystal bulk material in contact with a surface of the liquid crystal bulk material; and- between the second confinement substrate and the liquid crystal bulk material; A second surface director alignment layer disposed in contact with the surface of the liquid crystal bulk material;
A liquid crystal device comprising:
At least one of the first and second surface director alignment layers, preferably both, comprise a composition as described above.

When a liquid crystal bulk material such as a liquid crystal layer in a liquid crystal device is contacted with an alignment material containing the polymer composition of the present invention, liquid crystal molecules in the bulk surface toward the alignment material are exposed on the surface of the alignment material. There is a tendency to orient in the direction of the side groups attached to the compound, eg the polymer backbone. For example, liquid crystal bulk molecules in contact with the first compound of the composition of the alignment layer tend to align horizontally or substantially horizontally (planar alignment), while liquid crystal bulk molecules in contact with the second compound are There is a tendency to align vertically or substantially vertically (homeotropic alignment).
By using the above-mentioned composition in the surface director alignment layer of the liquid crystal device, the pretilt alignment that can be controlled between the planar alignment and the vertical alignment of the liquid crystal molecules controls the concentration ratio of the first compound to the second compound Can be achieved by means of: By introducing a pretilt in the alignment of the liquid crystal bulk, several important properties of the liquid crystal device have changed. The greater the pretilt, the lower the threshold voltage and the shorter the rise time and fall time. In accordance with the present invention, the ratio of the first compound to the second compound can be adjusted to achieve the desired surface director pretilt angle.

In a fourth aspect, the present invention provides the following steps:
-Preparing a confinement substrate;
-Placing an alignment layer comprising a composition as described herein on the surface of the substrate; and-placing a liquid crystal bulk material in contact with the alignment layer, as described above The present invention relates to a method for manufacturing a liquid crystal device. In particular, the step of disposing an alignment layer can include the step of coating the surface with a prefabricated composition as described above.
Employing a composition as described above to provide an alignment layer in the manufacture of liquid crystal devices results in the performance of the resulting alignment layer compared to prior art methods that achieve a controllable surface director pretilt. It is very advantageous because it is less sensitive to processing parameters such as layer thickness changes, humidity and temperature, and deposition techniques. Therefore, the method of the present invention has good reproducibility. Furthermore, the manufacturing method is simplified by the fact that only one composition is used instead of the two as in the prior art methods such as Bos to form the alignment layer.

The present invention will now be described in more detail with reference to the following accompanying drawings:
FIG. 1 is a graph showing a logical model of tilt orientation (tilt orientation); FIG. 2 shows a side chain polymer each having a linear pendant side group attached to the side and end, and a polymer having both a side group attached to the end and a side group attached to the side; FIG. 3 shows a liquid crystal device according to an embodiment of the invention; FIG. 4 is a graph showing the pretilt angle obtained using a composition according to an embodiment of the invention as an alignment layer in a liquid crystal cell; FIG. 5 is another graph showing the pretilt angle obtained using the composition according to an embodiment of the present invention as an alignment layer in a liquid crystal cell.

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to compositions suitable for use as or in a surface director alignment layer, the synthesis of such compositions and the use of such compositions as surface director alignment layers. The present invention relates to a liquid crystal device such as a liquid crystal display.
The present inventors independently used the first compound that produces the first pretilt angle in the surface director alignment layer alone and the second compound that produces the second pretilt angle in the surface director alignment layer. It has been found that a homogeneous mixture with the second compound when used in can result in a composition that produces a desired pretilt angle different from the respective pretilt angles of the individual first and second compounds. The inventors have also found that the desired pretilt angle can be controlled by controlling the concentration of at least one of the first and second compounds.

We present a logical model of tilt orientation (tilt orientation) (TA).
According to this model shown in FIG. 1, the tilt angles promoted by each of the PA (“first”) and VA (“second”) compounds of the mixture are θ ₁ = 0 ° and θ ₂ = 90 °, respectively. , When they have equal orientation constraint strengths u, ie u = u ₂ / u ₁ = 1 (where u ₁ and u ₂ are respectively due to the directivity to the center of PA and VA, respectively) The pretilt angle as a function of the PA compound concentration is the first order from VA to PA at a PA compound concentration c ^* equal to 50%. (See FIG. 1). If θ ₁ = 0 ° and θ ₂ = 90 °, but u ≠ 1, the concentration c ^{* at} which a sudden change in orientation from VA to PA will depart from the 50% value. At stronger PA constraints, ie u = u ₂ / u ₁ > 1, the concentration c ^* <50%. Conversely, weaker PA binding, i.e., <in ^{1, c *> u = u} 2 / u 1 is 50%. Importantly, as long as θ ₁ = 0 ° and θ ₂ = 90 °, the transition from VA to PA as a function of c is first order. In FIG. 1, the solid curve indicates θ ₂ = 85 °, and the dotted curve indicates θ ₂ = 89.5 °.

However, if θ ₂ ≠ 90 ° and / or θ ₁ ≠ 0 °, the transition from VA to PA is converted from primary to secondary, ie, continuous. This provides that the compound of the mixture is θ ₂ ≠ 90 ° and / or θ ₁ ≠ 0 ° to provide continuous control of pretilt over a wide range of concentrations of different compounds (alignment centers) in the alignment material composition. Means that should be provided. Therefore, the alignment material composition should contain compounds that promote VA and PA, respectively, and at least one of them should have a certain pretilt. In fact, after mechanical processing such as rubbing, each of the VA and PA compounds has θ ₂ ≠ 90 ° and θ ₁ ≠ 0 °, respectively, instead of the initial θ ₂ = 90 ° and θ ₁ = 0 °. Facilitate. Thus, the composition for the production of the alignment layer is a VA tilt θ ₂ ≠ 90 ° and / or PA after mechanical treatment such as unidirectional rubbing with a cotton, nylon or polyester fabric, for example. Compounds that promote VA and PA, respectively, with tilt θ ₁ ≠ 0 ° should be included.

By introducing a pretilt in the alignment of the liquid crystal bulk, several important properties of the liquid crystal device have changed. The greater the pretilt, the lower the threshold voltage and the shorter the rise time and fall time.
The first and second compounds of the present invention are miscible, thus allowing the formation of a uniform mixture. In general, in order for two compounds to be miscible, the compounds must be similar in terms of physicochemical properties. For example, the compounds may have only slight differences in chemical structure, polarity, surface energy, etc.

  When used in a surface director alignment layer in contact with a liquid crystal bulk material, the composition according to the invention thus causes the desired liquid crystal bulk molecule pretilt angle with respect to the alignment layer without application of an electric field. Advantageously, as a result of the composition being a homogeneous mixture, the alignment layer is uniform, thus avoiding many of the disadvantages of the prior art. For example, since the formation on the nano-domain is avoided, the influence of the layer thickness on the performance of the alignment layer is reduced. Thus, the properties of the alignment layer comprising the composition according to the invention are less sensitive to processing parameters such as humidity, temperature and deposition techniques. Similarly, the reproducibility of the alignment properties of the alignment layer according to the invention is very high compared to that of the alignment layer produced according to the prior art method.

In aspects of the invention, the first pretilt angle may range from 0 ° to 45 °, or from 0 ° to less than 45 °. In many cases, the pretilt angle of the liquid crystal bulk molecules is ideally as close to 45 ° or close to 45 ° as possible. In practice, however, such large angles are difficult to achieve using only one surface director alignment compound. However, with the composition according to the invention, the desired pretilt angle, for example 45 °, can be achieved. The first pretilt angle is preferably in the range of 5 ° to 25 °, since pretilt angles that deviate slightly from planar (θ ₁ ≠ 0 °) or vertical (θ ₂ ≠ 90 °) orientation are generally more easily obtained. It is. Otherwise, the first pretilt angle can be very small, substantially 0 °. In this context, “substantially 0 °” means from 0 ° to about 10 °, for example 0 ° to 5 ° or 0 ° to 2 °.

Accordingly, the second pretilt angle may be in the range of 45 ° to 90 ° (45 ° <θ ₂ <90 °), preferably 70 ° to 85 °. Otherwise, the second pretilt angle can be substantially 90 °. In this context, “substantially 90 °” means about 80 ° to 90 °, such as 85 ° to 90 ° or 88 ° to 90 °.
The pretilt angle induced by the alignment layer can be determined by methods known in the art, such as the crystal rotation method widely used in liquid crystal research (TJ Scheffer, J. Nehring, J. Appl. Phys., 48, 1783, 1979).
Typically, the first pretilt angle is smaller than the desired pretilt angle and the second pretilt angle is larger than the desired pretilt angle. Thus, the desired pretilt angle can be controlled between the first and second pretilt angles by controlling the concentration of the compound in the composition.

The compounds of the composition according to the invention can orient the liquid crystal molecules through several mechanisms such as surface energy, steric interactions and elastic forces.
Surface energy is the product of a complex interaction between the liquid crystal and the supporting solid surface. These interactions include van der Waals and dipole interactions, hydrogen bonds, and the like. Most orientation methods for obtaining VA are based on surface energy mechanisms. The smaller the surface energy, the better the VA orientation. A typical example is a fluorinated polymer material used for VA alignment. Conversely, high surface energy results in planar alignment (PA) of the liquid crystal. Alignment materials with low and high surface energy are widely used today in LCD manufacturing technology.

The oldest alignment method is a rubbing method using the elastic force of liquid crystal. According to this method, the surface of the support substrate in contact with the liquid crystal is rubbed in one direction to promote planar or near-planar alignment in a preferred direction along the rubbing direction. The rubbing method creates nano / micro grooves on this surface and orients the liquid crystal molecules along the grooves to minimize the elastic force, resulting in a forced surface on the liquid crystal by the rubbed surface. Orientation occurs. The rubbing method is widely used in current LCD technology.
The combination of the first and second compounds is selected to obtain the desired pretilt or orientation of the liquid crystal bulk material. The preferred combination for a particular application will depend on a number of factors, such as the working temperature, the type of LC-bulk material, and other factors.

In another embodiment of the present invention, the first compound comprises a first side group represented by S ¹ and the second compound comprises a second side group represented by S ² . Typically, the first side group can be attached to the first repeat unit of the polymer backbone and the second side group can be attached to the second repeat unit of the polymer backbone. Thus, according to an aspect of the present invention, the composition comprises a polymer backbone functionalized with said first and / or second side groups and optionally other functional groups as described below. obtain.
The first and second repeating units may be exactly the same repeating units as the polymer backbone. Thus, by including the first and second compounds in the same polymer, their miscibility can be ensured when the polymerization is carried out from a solution of monomers.
Otherwise, the first and second repeat units are repeat units of different polymer backbones. Thus, the first compound can include a first polymer and the second compound can include a second polymer. Importantly, the first and second polymers should be miscible to form a uniform composition as described above.

（式中、Ｚは、繰り返し単位のようなポリマー骨格の１部分を表し、及び、Ｌは、任意のリンカー部分を表す。）に従う複数の第一側基を含むポリマーであり得る。 Accordingly, the first compound has the following general formula:

(Wherein Z represents a portion of the polymer backbone such as a repeating unit, and L represents an optional linker moiety) can be a polymer comprising a plurality of first side groups.

（式中、Ｚは、繰り返し単位のようなポリマー骨格の１部分を表し、及び、Ｌは、任意のリンカーを表す。）に従う基を含む、前記第一側基又は異なるポリマーで機能化された上記ポリマーと同じポリマーであり得るポリマーであり得る。
例えば、第一及び第二側基の少なくとも１つは、例えば、フェニル基を含む芳香族であり得る。 The second compound has the general formula

Wherein Z represents one part of the polymer backbone, such as a repeating unit, and L represents any linker, functionalized with said first side group or with a different polymer. It can be a polymer that can be the same polymer as the polymer.
For example, at least one of the first and second side groups can be aromatic including, for example, a phenyl group.

The side groups S ¹ and S ² are each typically between 0 and 30, for example, 0 or 5 and 15 linking atoms (wherein the 0 linking atom is a side group via a direct bond). The case where it is directly bonded on the polymer backbone is shown.) Can be bonded to the polymer backbone by a spacer group L containing. However, spacer groups longer than 30 bonded atoms are also contemplated for use in the present invention.
The spacer group L can be utilized, for example, to facilitate the attachment of the side groups S ¹ or S ^{2 to} the polymer backbone and can also be used to increase the mobility of the attached side groups.
The spacer group L is typically any saturated or unsaturated hydrocarbon chain, such as an alkyl group, alkenyl group, aryl group, alkylaryl group, alkoxy group or polyether group, aryloxy group or siloxane chain. Is replaced by Typical examples include C ₅ -C ₁₅ alkyl or alkyloxy chain.

At least one of the first and second side groups S ¹ and S ² exhibits shape anisotropy. For example, the first side group can exhibit shape anisotropy or the second side group can exhibit shape anisotropy. Otherwise, both the first and second side groups can exhibit shape anisotropy.
As used herein, the term “side group exhibiting shape anisotropy” refers to a molecule that exhibits shape anisotropy in its actual environment. A side group exhibiting shape anisotropy shows a clear difference between its minor axis (s) and its major axis (s) and is relatively rigid in its structure.

In the embodiment of the present invention, the side group exhibiting shape anisotropy is a mesogen side group.
Liquid crystal handbook, Volume 1, Basics, pub. As defined in John & Sons Inc, 1998, the term “mesogen” generally relates to structures that are compatible with mesophase formation. This definition is used throughout this specification. Accordingly, the mesogenic side group is a side group having an intermediate layer structure.
In the “Liquid Crystal Handbook (see above)”, a mesogen is equivalent to an “intermediate compound”, ie a compound that can exist as an intermediate phase, ie a liquid crystal phase, under suitable conditions of temperature, pressure and concentration. It is.
Mesogen is a typical example of a molecule that exhibits shape anisotropy. Therefore, side groups containing mesogens fall under this definition. On the other hand, the side groups are mesogenic side groups and need not be mesogens, as well as mesogenic side groups that are not mesogens are also contemplated for use in the present invention.

At least one of the first and second side groups may have a linear shape. For example, the first side group can be linear or the second side group can be linear. Otherwise, both the first and second side groups can be linear. A straight-chain side group has a well-defined long axis extending along the main extension of the molecule and a short axis perpendicular to the long axis. Linear side groups exhibiting shape anisotropy are also known as different terms such as calamitic side groups, lath-like side groups and rod-like side groups.
Furthermore, at least one of the first and second side groups may have a disc shape and is in a position parallel or perpendicular to the polymer backbone. Further, at least one of the first and second side groups may have an elongated, bent shape (“banana”), v-shape or bowl-shape that is attached to the polymer backbone at the sides or ends. The selection of side groups with anisotropic shapes can be extended by those skilled in the art to other anisotropic shapes other than those already mentioned.

The surface characteristics of the substrate affect the orientation of the mesogens of the liquid crystal layer that contacts the substrate surface and at least the contact surface between the substrate surface and the liquid crystal layer.
Typically, the contact surface conditions propagate through the liquid crystal layer, so that all liquid crystal layer alignment is affected by the alignment at the contact surface.
In particular, when the liquid crystal layer is in contact with side groups with shape anisotropy existing on the substrate surface, the liquid crystal molecules at the contact surface between the liquid crystal layer and the substrate surface are aligned in the direction of these side groups. Tend to.
For example, a group present on the substrate surface having a linear or disc shape anisotropy is basically aligned parallel to the substrate surface, and the liquid crystal molecules at the contact surface toward the substrate surface are also aligned with the substrate surface. Tend to be oriented parallel to
On the other hand, when a substrate surface having a group with linear or disc shape anisotropy that is basically oriented perpendicular to the substrate surface is used, mesogens at the contact surface toward the substrate surface also appear on the substrate surface. Tends to be oriented vertically

By utilizing the side groups having the specified shape anisotropy in the composition according to embodiments of the present invention, a liquid crystal material such as a liquid crystal layer of a liquid crystal device is oriented in the direction of the side groups bonded to the polymer skeleton. Tend. Depending on the shape of the first side group and the position of the side group attached to the polymer backbone and also the presence of other functional groups near the second side group and / or the first side group, shape anisotropy The first side group having can induce different orientations of the liquid crystal bulk molecules. For example, linear side groups bonded laterally to the polymer backbone can induce planar orientation. However, planar orientation can also be achieved using side groups of other shapes and bond positions. For example, small rigid groups such as phenyl groups, short chain alkyl groups or short chain arylalkyl groups can be used to achieve planar alignment of the liquid crystal. Furthermore, linear side groups attached terminally to the polymer backbone can induce vertical orientation. Vertical orientation can also be achieved, for example, using v-shaped side groups attached laterally (in the axis) to the polymer backbone. Thus, it is the combination of the specific shape of the side group and the specific bond position (terminal or side, respectively) that determines whether a planar or vertical orientation is derived.

One skilled in the art can select side groups with appropriate anisotropic shapes and bonds to the polymer backbone so that the desired orientation of the side groups relative to the surface of the alignment layer can be achieved.
As used herein, the term “terminally attached” is generally attached to the polymer backbone by means of a spacer attached to the side group at or near the end of the long axis of the side group molecule, thereby Reference is made to a linear side group exhibiting shape anisotropy in which the spacer is essentially parallel to the long axis of the side group. For example, in a rod-like side group, such as a calamitic mesogenic group, the binding position is at or near the terminal end of the side group, as shown in FIG. 2a.

As used herein, the term “side-attached” is generally attached to the polymer backbone by means of a spacer attached to a side group so that the spacer is as shown in FIG. Reference is made to a straight-chain side group exhibiting shape anisotropy which is essentially perpendicular to the long axis of the side group molecule. The side groups shown in FIGS. 2a and 2b can be attached to the same polymer backbone, as shown in FIG. 2c.
For further definitions of terms relating to liquid crystals and related terms, the reference is “Definitions of basic terms rela- ting to low-molar-mass and polymer liquid crystals” (IUPAC Recommendations 2001, Pure ApI, Ampl. pp 845-895, 2001), all of which are incorporated herein by reference.

The combination of the first and second compounds is selected to obtain the desired pretilt or liquid crystal bulk material orientation. The preferred combination for a particular application will depend on many factors, such as the working temperature, the type of liquid crystal bulk material, as well as other factors.
By providing a composition comprising a selected portion of the first compound and a selected portion of the second compound, a desired tilt angle of the liquid crystal material in contact with the composition can be obtained. Otherwise, the first and second side groups in a given ratio can be attached to the same polymer backbone.

In an embodiment of the present invention, in addition to the first side group S ¹ and the second side group S ² , the polymer or the first and second polymers are independently, optionally and additionally, one or more types. The following repeating unit groups may be included:
-A third group of unfunctionalized repeating units;
A fourth group, wherein each repeating unit in the fourth group is functionalized with a pendant side chain S ⁴ capable of fixing the polymer to the substrate;
A fifth group, wherein each repeating unit in the fifth group is independently functionalized with a pendant side chain S ⁵ selected from an aliphatic group and an aromatic group;
- a sixth group, each repeating unit in said six groups, are functionalized with ion migration inhibitor S ⁶ groups.
Other types of repeat units other than those described above can also be incorporated into the polymers according to embodiments of the present invention.

Side chains S ⁴ and S ⁵ can each be attached to the polymer backbone by means of spacer fragments L as described above, if necessary.
Enveloping the repeating units of the polymer backbone where the side chains are not bound to the backbone can result in a space between the first and / or second side chains.
In embodiments of the present invention, the anchoring side group S ⁴ can preferably be used to anchor the polymer to the underlying substrate. The immobilizing side chain group S ⁴ is typically an optionally substituted C ₂ to C ₂₀ , eg, C, with a functional group in the polymer backbone or at the end remote from the polymer backbone. ₂ to C ₈ hydrocarbon chain, this functionalized group is a chemical group on the substrate surface introduced by preactivation on the substrate surface, such as, but not limited to, a glass surface A bond such as a covalent bond, an ionic bond or a hydrogen bond can be formed on the above free hydroxyl group or, for example, an epoxy group, an amino group, a thiol group or an isocyano group.

Non-limiting examples of such functionalized groups suitable in the anchoring side chain include amino groups, hydroxy groups, isocyano groups and glycidyl groups. One skilled in the art will be able to select a suitable functionalization on the anchoring group depending on the substrate material.
Non-limiting examples of anchored side chain groups S ⁴ are as described above, where Z represents a part of the polymer backbone, L is a spacer group, preferably 1 to 10, for example 1 to 5 A spacer group having the length of a spacer atom, such as an alkyl spacer, as disclosed in structural formulas (III) to (VI) shown below:

The physicochemical properties of the composition according to embodiments of the present invention, such as glass transition temperature Tg, elastic modulus, deposited film coherence, film smoothness, wetting properties, surface energy, etc., are optionally substituted, eg, heteroatoms Halogenated, eg, fluorinated, branched or straight chain aliphatic and aromatic groups, such as alkyl groups, aryl groups or alkylaryl groups, polyether groups, siloxane groups, or alcohols, substituted with It can be adjusted to the desired value by incorporating into the polymer backbone a repeating unit comprising a side chain S ⁵ selected from the group.

Typical examples of S ⁵ -side groups are optionally fluorinated, eg perfluorinated, alkyl groups having 1 to 18 carbon atoms, eg alkyl groups having 4 to 12 carbon atoms or alcohols. Groups, and those groups defined above as spacer L. For example, the S ⁵ group is an alkyl chain typically reduces the Tg of the polymer, whereas, S ⁵ group is an aryl group generally increases the Tg of the polymer.
As described above, in the polymer (s) or polymer (s) according to embodiments of the present invention in which some of the repeating units are functionalized with first and / or second side groups, the polymer is also a side chain S ^5. More preferably, it also includes a repeating unit functionalized with a linear side chain S ⁵ . In such polymers, the ratio of S ¹ or S ² to S ⁵ side groups ranges from 1:10 to 10: 1.
S ⁵ side groups in such S ¹ and / or polymers functionalized with S ² side groups introduced a space between the adjacent S ¹ and / or S ² side groups, thus, the individual S ¹ And / or the mobility of the S ² side group is increased.

S ⁶ groups that inhibit ion migration are utilized in the alignment layer to reduce the concentration of mobile ions in the liquid crystal bulk material, and thereby to reduce the conductivity of the liquid crystal bulk material. The Groups that inhibit ion transfer are typically strongly polarized, ion-attracting, non-ionic groups. Examples of groups that inhibit ion transfer are other groups including materials conventionally known as ion traps, such as hydroxyl groups and coronands.

  In an embodiment of the present invention, the polymer is a cross-linking group linking two separate repeat units, for example, an internal cross-link connecting two repeat units in the same polymer backbone or at least one of the first or second polymer. Can be cross-linked by external cross-linking connecting two separate polymer backbone chains. Similarly, cross-linking groups can be used to link the polymer containing the first and / or second side groups with other polymers.

In the present invention, cross-linking is preferably performed with photoreactive groups such as those described below, however, it is possible to use thermally induced reactions using any reactive group attached to the polymer. It can also be achieved.
The first and / or second polymer may comprise reactive, preferably photo-reactive side groups. The photo-reactive side groups can be the first and / or second side groups or they can be separate side groups.
Reactive side groups can be used to fix the resulting alignment layer alignment, thereby reducing sensitivity to temperature-induced changes.

  Photoreactive side groups with shape anisotropy can be used, for example, to dimerize / polymerize only those groups that have a specific direction compared to linearly polarized light, ie polarized light Thus, it can be oriented in the desired direction by illumination with light to obtain the preferred direction of those groups in the polymer. Thus, advantageously, photo-alignment can be utilized to align and crosslink materials, whereby the alignment direction is a one-step method that achieves higher thermal stability. Compared to the rubbing method, the light-orientation also has the advantage of not inducing dirt, scratches or electrostatic discharge. Similarly, it is easier to control accurately and results in high yields.

Dimerization / polymerization of reactive side groups is between two reactive side groups attached to one and the same polymer chain, or two reactive side groups attached to distant polymer chains. Between can be achieved.
Possible photoreactive groups with shape anisotropy include, but are not limited to, chalcones, coumarins, and cinnamon.

The first and / or second polymer may include photoresponsive side groups. The photoreactive side group can be an anisotropic S ¹ / S ² group or can be a remote side group.
A photoresponsive side group with shape anisotropy can be oriented in a desired direction, for example, by illumination with linearly polarized light. For example, and in combination with photoreactive groups, light can be used to direct the side groups, after which dimerization / polymerization as described above has similar advantages to the photoreactive groups described above for liquid crystal alignment. Along with this, it can be used to irreversibly fix the obtained direction. In this case, the direction can be achieved by a photoresponsive group with shape anisotropy, so the photoreactive group need not have shape anisotropy.

Otherwise, the photoresponsive group is directed by light at a high temperature, after which the temperature is lowered, thereby achieving irreversible immobilization of direction. Suitable photoresponsive groups for use in the present invention include, but are not limited to, azo-containing groups, stilbenes, and the like.
The polymer backbone of the polymer comprising said first and / or second side groups according to an embodiment of the invention can in principle be bonded to the first and second side groups as described above or Is capable of binding to any one of the first and second side groups and is miscible with the organic polymer backbone to which the other one or both of the first and second side groups are attached; It can be any organic polymer backbone.
Examples of suitable polymer backbones include, but are not limited to, polyamides, maleimide-N-vinyl pyrrolidone-copolymers, polyvinyl acetals, derivatives thereof and the like.

  In the first approach, the first and / or second side groups are grafted onto the prepolymerized polymer backbone. In a first variation of this first approach, the side groups are first attached to a spacer fragment and the spacer-side group assembly is then grafted onto the polymer backbone. In a second variation of this first approach, the spacer fragment is grafted onto the polymer backbone and the side groups are then attached to the grafted spacer fragment.

In a second approach, the polymer is synthesized by copolymerization of different monomers where the monomers contain side groups such as the first and / or second side groups.
In the combination of the first and second approaches, some of the side groups are attached to the polymer by means of co-polymerization according to the second approach described above, and some of the side groups are in accordance with the first approach described above, Grafted onto the polymer backbone.

The surface director alignment material of the present invention comprises a composition as described above, for example a polymer composition as described above, alone or in combination with at least one further polymer.
In other embodiments, the surface director alignment material of the present invention further comprises at least one additional polymer that is not itself protected by the scope of the present invention. The purpose of this at least one further polymer is, for example: to form an embedded matrix for the composition of the invention, thereby firmly bonding the alignment material to the substrate; the invention in the alignment material of the invention Effectively reducing the concentration of the composition; or promoting an effective uniform and stable alignment layer.

Additional polymers for use in the surface director alignment materials of the present invention can be crosslinked or uncrosslinked polymers.
A surface director alignment layer is a layer in contact with a liquid crystal material that tends to align liquid crystal molecules at or near the contact surface between the liquid crystal material and the alignment layer.
The surface director alignment layer comprising the composition of the present invention tends to align liquid crystal molecules in the pretilt direction, which is advantageous in many applications, as will be appreciated by those skilled in the art.

  Typically, the surface alignment layer is disposed on the substrate. Such a surface director alignment layer is manufactured by providing a substrate and placing a surface director alignment material comprising the composition of the present invention on the substrate surface in contact with the liquid crystal. The composition can be provided as a solution of the first and second components in at least a suitable solvent.

  In one embodiment, the surface director alignment material of the present invention is supplied and dissolved, dispersed or suspended in a liquid medium such as a volatile solvent. The solution / dispersion / suspension is then applied onto the substrate surface, followed by removal of the liquid medium. Suitable coating methods include, but are not limited to, conventional deposition methods such as spin coating, spray coating, doctor blade coating, roll coating, flexographic printing, ink jet printing, dipping and the like.

  In another embodiment, a precursor such as a mixture of monomers and / or prepolymers for the surface director alignment material in the liquid medium as a reaction mixture is applied onto the substrate surface, followed directly by the substrate surface. Above it is polymerized in situ into the surface director alignment material of the invention.

The liquid crystal device of the present invention includes at least one confinement substrate, a liquid crystal bulk layer, and a surface director alignment layer disposed between the liquid crystal bulk layer and the substrate, wherein the surface director alignment layer is the Including a composition.
The liquid crystal device of the present invention may be single-sided where the liquid crystal material is disposed on one confining substrate with the open interface on the other side, or the liquid crystal material is It can be double-sided sandwiched between the first and second substrates.

In a double-side liquid crystal device, the surface director alignment material of the present invention can be disposed on only one side, ie between the liquid crystal material and one of the substrates, or on both sides, ie between the liquid crystal material and both substrates. . The liquid crystal device can be double-sided, but it even has the alignment layer of the present invention deposited on only one side of the confinement substrate.
The presence of a surface director alignment layer comprising the composition of the invention results in a pretilt-direction of the liquid crystal material, at least at or near the contact surface towards the alignment layer direction.

As illustrated in the figures, the sizes of layers and regions are exaggerated for illustrative purposes, and are thus provided to illustrate the general structure of aspects of the present invention.
The double side liquid crystal device 100, which is illustrated in FIG. 3, includes a first confinement substrate 101 and a second confinement substrate 102 that are spaced apart from each other. A liquid crystal material 103 is sandwiched between the substrates 101 and 102 and disposed between the substrates 101 and 102.

The surface director alignment layer 104 of the present invention is disposed on the first substrate 101 in contact with the liquid crystal material 103. The surface director alignment layer 104 can be chemically bonded to the substrate 101 by, for example, the presence of side groups that are immobilized on the polymer of the composition.
The surface director alignment layer 104 includes at least one of the compositions of the present invention as described above, and thus the surface director alignment layer 104 is at least at or near the contact surface toward the surface director alignment layer 104. The pretilt direction of the liquid crystal material 103 is promoted.

One skilled in the art will recognize that the liquid crystal device 100 of the present invention may include means for obtaining an electric field in the liquid crystal material 103. Changes in the electric field typically result in switching of the liquid crystal material.
For example, such means are represented by a set of electrodes. In the embodiment described in FIG. 3, the first electrode 105 is disposed between the alignment layer 104 and the substrate 101, and the second electrode 107 is disposed on the second substrate 102.
The surface director alignment layer 104 will induce a pre-tilt of the surface director of the liquid crystal material 103.
The second alignment layer 106 is disposed between the second substrate 102 and the liquid crystal material 103. This second alignment layer may also comprise the composition of the invention or alternatively may be another type of alignment layer material.

Commercially available chemical compounds were used with the following exceptions: i) N-vinyl-pyrrolidone (NVP) was passed through aluminum oxide prior to use to remove added stabilizer. Ii) When dry THF was required, it was dried by passing normal THF through aluminum oxide before use. Aluminum oxide activated
neutral Blockmann 1.58 (CAS 1344-28-1) was used for THF drying and NVP purification.
In all the following examples, standard reactions well known to those skilled in the art were used for the preparation of the polymers.
Poly (vinyl acetal) based alignment materials Polymeric alignment materials can be made, for example, by functionalization of poly (vinyl alcohol) (PVA) with aldehydes that give poly (vinyl acetal). The production of these materials and the side groups used is as follows.

スキーム１．ＶＡポリ（ビニルアセタール）ポリマー製造 Example 1: Poly (vinyl acetal) having terminally attached side groups (Polymer III)

Scheme 1. VA poly (vinyl acetal) polymer manufacture

Stock solution dried 1.01 g of poly (vinyl alcohol) (M _n = 16000, hydrolyzed to 98% (commercially available, manufactured from poly (vinyl acetate)) and 1.0 g of lithium chloride Prepared by adding to 100 mL of dimethylformamide (DMF). The mixture was heated to 90 ° C. with stirring. When the polymer dissolved, the solution was allowed to reach room temperature. This solution contained 4.6 mmol hydroxyl groups per 20 mL. To 20 mL of the poly (vinyl alcohol) solution was added 0.230 g of II equal to 0.42 mmol of aldehyde, 0.490 g of II equal to 1.84 mmol of hexadecanol and 0.2 g of p-toluenesulfonic acid.
The reaction mixture was heated to 60 ° C. for 12 hours. The solution was allowed to reach room temperature and then poured into stirred methanol resulting in precipitation of poly (vinyl acetal). The polymer was purified by two precipitations from chloroform to methanol and another precipitation from chloroform to petroleum ether / ethyl acetate 9/1. 0.57 g of dried polymer was obtained.
NMR (CDCl ₃ ): δ, pattern; 0.88 t; 1.0 t, methyl group from alkyl group, methyl group from mesogen; 1.1-2.0 3 broad peaks; 3.6-4 .8 Broad peak from the methylene group next to the oxygen atom in the polymer main and side chains;
95, d 2H in mesogen; 7.6, dd, 4H in mesogen; 8.05, d, 2H in mesogen The ratio of mesogen to alkyl group was calculated using the methyl signals from two different methyl groups. /3.7.

  The amount of polymer relative to the aldehyde added during the reaction may need to be annotated. At each substitution event in the reaction, two adjacent hydroxyl groups react. This leads to the fact that a certain number of hydroxyl groups are captured between the reacted groups and as a consequence are not available for the reaction. The amount of group supplemented was calculated using statistics and found to be 14%. This means that there is an excess of 0.28 mmol since up to 3.96 mmol of hydroxyl groups can react during this reaction and can react to an aldehyde amount of 2.26 mmol.

  This material was deposited as an alignment layer on the inner surface of the glass substrate of a sandwich cell made according to the described procedure. The cell was filled with nematic liquid crystal MLC6608 with negative dielectric anisotropy (Δε <0) and was first tested under a polarizing microscope to identify the type of liquid crystal alignment promoted by the alignment layer. . The observed orientation in this cell was homeotropic, ie along the substrate normal. Next, the pretilt angle in the preferred direction of liquid crystal alignment from the substrate normal was measured by means of a Muller matrix spectrometer. When the alignment layer was mechanically rubbed, a small pretilt of less than 1 degree was obtained from homeotropic alignment. This polymer can therefore be used as a high (close to VA) tilt component of a composition according to an embodiment of the invention.

スキーム２．ＶＡポリ（ビニルアセタール）側基及びポリマー製造 Example 2 Poly (vinyl acetal) with pendant side groups (polymer V)

Scheme 2. VA poly (vinyl acetal) side group and polymer production

Polymer V was prepared using the same experimental conditions as for Polymer III in Example 1, except that 0.5 mmol of Polymer V and 2.0 mmol of Polymer II were used, and the polymer in Example 1 It meant that there was a greater excess of aldehyde than in the manufacture of IV.
The experimental procedure and post-treatment were the same as in Example 1.
Yield: 0.60 g. NMR (CDCl ₃ ): δ, pattern; 0.85 t; 1.1-2.0 4 broad peaks; 3.5-4.8 From the methylene group next to the oxygen atom in the polymer main and side chains Broad peak; 6.9, in m 4H mesogen; 7.1, d, 2H
In mesogens; 8.1, d, 2H In mesogens The ratio of mesogen to alkyl group was calculated from the methyl group and aromatic signal and was equal to 1 / 3.8.

  This material was deposited as an alignment layer on the inner surface of the glass substrate of a sandwich cell made according to the described procedure. The cell was filled with nematic liquid crystal MLC6608 with negative dielectric anisotropy (Δε <0) and was first tested under a polarizing microscope to identify the type of liquid crystal alignment promoted by the alignment layer. . The observed orientation in this cell was homeotropic, ie along the substrate normal. Next, the pretilt angle in the preferred direction of liquid crystal alignment from the substrate normal was measured by means of a Muller matrix spectrometer. When the alignment layer was mechanically rubbed, a small pretilt of less than 1 degree was obtained from homeotropic alignment. This polymer can therefore be used as a high (close to VA) tilt component of a composition according to an embodiment of the invention.

スキーム３．ＰＡポリ（ビニルアセタール）ポリマー製造 Example 3: Poly (vinyl acetal) with side groups attached at the sides (Polymer VII)

Scheme 3. PA poly (vinyl acetal) polymer production

130 mg of PVA 16000 and 0.2 g of lithium chloride were added to 20 mL of dry DMF and heated to 90 ° C. to obtain a clear solution. The 130 mg of PVA used contains 2.90 mmol of hydroxyl groups which 86% can substitute according to statistics. This is equivalent to 2.49 mmol of reactive groups that can be used. 300 mg (0.51 mmol) of VI and 163 mg of octanol (commercial chemical shown to be 80% in aldehyde by NMR being 1.02 mmol) into a polymer solution combined with 0.3 g of toluenesulfonic acid. Added. The reaction was carried out at 60 ° C. for 1 week. The post-treatment was similar to that described in Example 1 for Polymer III. Yield: 110 mg. NMR analysis showed 27% to be mesogens and 73% to be alkyl groups.
NMR (CDCl ₃ ): δ, pattern; 0.9 m; 1.1-1.7 broad peak; 1.8, m; 3.6-4.8 broad peak; 6.5, d; , D; 7.1, d; 8.0, d

  This material was deposited as an alignment layer on the inner surface of the glass substrate of a sandwich cell made according to the described procedure. The cell is filled with nematic liquid crystal MLC6873-100 with positive dielectric anisotropy (Δε> 0) and first tested under a polarizing microscope to identify the type of liquid crystal alignment promoted by the alignment layer. It was done. The observed orientation in this cell was homogeneous, ie essentially parallel to the substrate. Thus, it can be used as a low (close to planar orientation) tilt component of a composition according to an embodiment of the invention.

Maleimide N-vinylpyrrolidone copolymer The polymeric alignment material can also be made, for example, by copolymerization of a functionalized maleimide and N-vinylpyrrolidone. The preparation of the side groups used with these materials is shown below.

スキーム４．ＶＡコポリマー製造 Example 4: Maleimide-N-vinylpyrrolidone copolymer with terminally attached side groups (copolymer XVI)

Scheme 4. VA copolymer production

Maleimide XIV 0.4 mmol (234 mg), N-dodecylmaleimide XV 1.6 mmol (424 mg), NVP 2.0 mmol (222 mg) purified by passing through aluminum oxide and 2,2′-azobis (2-methylpropionitrile) ( (AIBN) 0.12 mmol (19 mg) was dissolved in 10 mL of benzene in a round bottom flask and the flask was sealed with a rubber septum. A vacuum and subsequent nitrogen inflow was applied through the septum via a syringe needle. A vacuum-nitrogen inflow cycle was used repeatedly 10 times to remove oxygen in the flask. The flask was heated in an oil bath heat defined up to 60 ° C. After 15 hours, the solution was poured into methanol and the formed polymer precipitated. The polymer was reprecipitated twice from chloroform into methanol and at least once from chloroform to an acetone / methanol 1/3 mixture. The solvent was decanted and pure methanol was added. Finally, the polymer was placed in a vial and heated on a hot plate to drive off residual solvent. The last traces of solvent were removed by heating the polymer in a vacuum oven at 60 ° C. for 2 hours.
Yield: 0.7 g, 80%. NMR (CDCl ₃ ): δ, pattern; 0.9, t; 1-5 side group signal at the top of the broad backbone signal; 6.9, 2d; 7.1, d; 8.1, d.
The polymer composition with respect to the mesogen / alkyl ratio was determined using methyl and aromatic signals in ¹ H NMR and found to be 1 / 4.2. This means that ignoring the pyrrolidone group, 19.2% of the side groups are mesogens.

This material was deposited as an alignment layer on the inner surface of the glass substrate of a sandwich cell made according to the described procedure. The cell was filled with nematic liquid crystal MLC6608 with negative dielectric anisotropy (Δε <0) and was first tested under a polarizing microscope to identify the type of liquid crystal alignment promoted by the alignment layer. . The observed orientation in this cell was homeotropic, ie along the substrate normal. Next, the pretilt angle in the preferred direction of liquid crystal alignment from the substrate normal was measured by means of a Muller matrix spectrometer. When the alignment layer was mechanically rubbed, a small pretilt of less than 1 degree from VA was obtained. It can be used as a high tilt (close to VA) component of a composition for controlling pretilt in accordance with aspects of the present invention.

スキーム５．フッ化アルカンを伴うＶＡコポリマー製造 Example 5: Copolymer XVII

Scheme 5. VA copolymer production with fluorinated alkanes

VA copolymer: 0.5 mmol (331 mg) mesogenic maleimide XIII, 0.5 mmol (228 mg) hexylpropyl maleimide perfluoride XVII, 1.5 mmol (400 mg) dodecylmaleimide, 2.5 mmol (277 mg) purified by passing through aluminum oxide ) And 2,2′-azobis (2-methylpropionitrile) (AIBN) 0.15 mmol (25 mg) were dissolved in 25 mL of benzene. The polymerization was carried out in an oil bath at 60 ° C. for 40 hours. Purification by several reprecipitations from a few mL of chloroform into methanol and a single reprecipitation into methanol / acetone 2/1 gave the final polymer XVIII.
This material was tested in the same manner as in Example 1 with similar yields and properties. The material provides a VA orientation with a low filling rate due to the low surface energy of the fluorinated group.

スキーム６．ＰＡ共重合 Example 6: Maleimide-N-vinylpyrrolidone copolymer with side groups attached at the sides (copolymer XX)

Scheme 6. PA copolymerization

Maleimide XIX 0.4 mmol (265 mg), N-octylmaleimide 1.6 mmol (334 mg), NVP 2.0 mmol (222 mg) purified by passing through aluminum oxide and 2,2′-azobis (2-methylpropionitrile) ( AIBN) 0.12 mmol (19 mg) was dissolved in 10 mL of benzene. Polymerization and work-up were carried out according to the preparation of VA copolymer XX.
Yield: 0.66 g, 80%. NMR (CDCl ₃ ): δ, pattern; 0.9, t; 1-5
Side signal at the top of broad backbone signal; 6.5, d; 6.9, d; 7.1, d; 8.0, d.
The polymer composition for the mesogen / alkyl ratio was determined using methyl and aromatic signals in ¹ H NMR and found to be 1 / 1.8. This means that ignoring the pyrrolidone group, 36% of the side groups are mesogens.

  This material was deposited as an alignment layer on the inner surface of the glass substrate of a sandwich cell made according to the described procedure. The cell is filled with nematic liquid crystal MLC6873-100 with positive dielectric anisotropy (Δε> 0) and first tested under a polarizing microscope to identify the type of liquid crystal alignment promoted by the alignment layer. It was done. The observed orientation in this cell was homogeneous, ie essentially parallel to the substrate.

スキーム７．高Ｔ_gＶＡコポリマー Example 7: High T _g VA polymer

Scheme 7. High T _g VA copolymer

Maleimide XIII 0.40 mmol (180 mg), N-phenylmaleimide 1.6 mmol (277 mg), N-vinylpyrrolidone 2.0 mmol (222 mg) and 2,2′-azobis (2-methylpropionitrile) (AIBN) 0.12 mmol (19 mg) was dissolved in 10 mL of benzene. The mixture was polymerized and worked up as described in Example 1.
Yield: 0.26 g, 38%. NMR (CDCl ₃ ): δ, pattern; 0.9, bs; 1.1-5 side group signal on top of broad backbone signal; 6.9, bs; 7.0-7.6, bs
With firm side chains and mesogens, the glass temperature can be increased compared to those with soft alkane chains. This material exhibits a Tg of about 200 ° C. This material was deposited as an alignment layer on the inner surface of the glass substrate of a sandwich cell made according to the described procedure. The cell was filled with nematic liquid crystal MLC6608 with negative dielectric anisotropy (Δε <0) and was first tested under a polarizing microscope to identify the type of liquid crystal alignment promoted by the alignment layer. . Due to the VA characteristics of mesogen XIII and the PA characteristics of component XXVI, a pretilt that depends on the amount of each component is obtained when the alignment layer is mechanically rubbed. With the above ratio, the pretilt was 15 °. The alignment layer also showed good thermal stability.

スキーム８．“バナナ”コポリマー Example 8: Side-bound “banana” copolymer (hypothetical example)

Scheme 8. “Banana” copolymer

The “banana” copolymer was run following the same procedure as the PA copolymer described above using XXVII as the monomer.
The polymer is mixed with appropriate amounts of side chain precursors XXVII, vinylpyrrolidone, octylmaleimide, AIBN and benzene in a flask after oxygen has been removed by appropriate methods such as repeated vacuum and nitrogen wash cycles. And by stirring (eg, 12 hours at 60 ° C.). The reaction mixture is then poured into a suitable amount of an organic solvent such as methanol to precipitate a polymer according to structure XXVIII of Scheme 8. Compared to Examples 1 and 3, this is a method of creating a pretilt angle in the sample, using the same principle as mixing different VA and PA materials, but here using bent mesogens instead To do.
This polymer is expected to promote VA in most nematic liquid crystals.

スキーム９．“バナナ”コポリマー Example 9: "Banana" copolymer at the end (hypothetical example)

Scheme 9. “Banana” copolymer

The “banana” copolymer was run following the same procedure as the PA copolymer described above using XXIX as the monomer.
The polymer is mixed and stirred in a flask with appropriate amounts of side chain precursors XXIX, vinylpyrrolidone, octylmaleimide, AIBN and benzene after the oxygen has been removed in a suitable manner such as repeated vacuum and nitrogen wash cycles. For example, it is manufactured according to the above-mentioned embodiment by carrying out for 12 hours at 60 ° C. The reaction mixture is then poured into an appropriate amount of an organic solvent such as methanol to precipitate a polymer according to structure XXX of Scheme 9.
Compared to Examples 1 and 3, this is a method of creating a pretilt angle in the sample, using the same principle as mixing different VA and PA materials, but here using bent mesogens instead To do.

スキーム１０．バナナ及びＶＡコポリマー Example 10: End-linked “banana” and VA copolymer (hypothetical example)

Scheme 10. Banana and VA copolymer

The banana copolymer was run following the same procedure as the PA copolymer described above using I and XXIX as monomers.
Compared to the polymer of Example 9, this polymer has a reduced tendency to tilt due to the increased amount of linear vertical alignment.
The polymer is mixed with appropriate amounts of monomer I, monomer XXIX, vinylpyrrolidone, octylmaleimide, AIBN and benzene in a flask after oxygen has been removed by a suitable method such as repeated vacuum and nitrogen wash cycles. Prepared according to the previous examples by stirring (for example at 60 ° C. for 12 hours). The reaction mixture is then scheme 1
In order to precipitate a polymer according to zero structure XXXI, it is poured into an appropriate amount of an organic solvent such as methanol.
Compared to Examples 1 and 3, this is a method of creating a pretilt angle in the sample that uses the same principle as mixing different VA and PA materials, but here instead of a specific pretilt Use bent mesogen mixed with vertical alignment material for use as alignment layer with.

スキーム１１．配向層のＶＡ特性とＰＡ特性の間の比率を制御する任意の方法のためのＶＡ／ＰＡコポリマー製造 Example 11: Copolymer XXXII:

Scheme 11. VA / PA copolymer production for any method to control the ratio between the VA and PA properties of the alignment layer

Mixing two mesogens in the same polymer will produce the same results as mixing two polymers with these two mesogens and so will change the tilt angle in the liquid crystal bulk Another way to make it happen.
The polymer is prepared according to the previous example by mixing and stirring (eg, 12 hours at 60 ° C.) appropriate amounts of monomer I, monomer VII, vinyl pyrrolidone, dodecyl maleimide, AIBN and benzene in a flask. Almost all oxygen is first removed using a suitable method such as repeated vacuum and nitrogen cleaning cycles. The reaction mixture is then poured into a suitable amount of an organic solvent such as methanol to precipitate a copolymer according to structure XXXII of Scheme 11.

スキーム１３．フェニルベースのＰＡコポリマー Example 12: Phenyl-based PA copolymer

Scheme 13. Phenyl-based PA copolymer

PA copolymer: Phenylmaleimide XXVI 5 mmol (866 mg), NVP 5 mmol (555 mg) purified by passing through aluminum oxide and 0.3 mmol (48 mg) of 2,2′-azobis (2-methylpropionitrile) (AIBN) Dissolved in 30 mL. The polymerization was performed overnight at 60 ° C. in an oil bath. Purification by three reprecipitations from several mLs of chloroform into methanol formed polymer XXXIII.
Yield: 0.550 g, NMR (CDCl ₃ ): δ, pattern; number of protons; 1-5 side group signal on top of broad backbone signal; 6.9-7.35; broad peak from aromatic proton (polymer) Broad due to proximity to the skeleton)

This material was deposited as an alignment layer on the inner surface of the glass substrate of a sandwich cell made according to the described procedure. The cell is filled with nematic liquid crystal MLC6873-100 with positive dielectric anisotropy (Δε> 0) and first tested under a polarizing microscope to identify the type of liquid crystal alignment promoted by the alignment layer. It was done. The observed orientation in this cell was homogeneous, ie essentially parallel to the substrate. The alignment layer also showed good thermal stability.
It is soluble in NMP. As a common “extended” skeleton with high glass temperature and planar orientation, it can be used as a PA component together with a high tilt compound in the same polymer.

スキーム１３．ＰＡコポリマー Example 13: Biphenyl-based PA copolymer

Scheme 13. PA copolymer

  Maleimide 0.5 mmol (180 mg), N-ethylmaleimide 1 mmol (125 mg), NVP 1.5 mmol (166 mg) purified by passing through aluminum oxide and 2,2′-azobis (2-methylpropionitrile) (AIBN) ) 0.06 mmol (10 mg) was dissolved in 8 mL of benzene. The polymerization was performed overnight at 60 ° C. in an oil bath. Purification by three reprecipitations from a few mL of chloroform into methanol. Yield: 0.35

  This material was deposited as an alignment layer on the inner surface of the glass substrate of a sandwich cell made according to the described procedure. The cell is filled with nematic liquid crystal MLC6873-100 with positive dielectric anisotropy (Δε> 0) and first tested under a polarizing microscope to identify the type of liquid crystal alignment promoted by the alignment layer. It was done. The observed orientation in this cell was homogeneous, ie essentially parallel to the substrate.

Mixture of VA and PA materials to obtain a tilted (tilted) orientation of the liquid crystal. To obtain a tilted (tilted) orientation, promote vertical and planar orientation, respectively, and Mix materials that have and are thereby miscible. For example, such a material with side groups exhibiting linear shape anisotropy is illustrated schematically in FIG. 2, where FIG. 2a presents the VA material and FIG. Present. The mesogenic group of the VA material has a longitudinal (terminal) bond to the polymer backbone, whereas the mesogenic group of the PA material has a lateral (side) bond to the polymer backbone. These materials are mixed in different proportions to obtain material compositions that promote different pretilt angles. FIG. 2c presents a polymeric material in which the side groups are with mixed bonds of the side and end bonds, respectively.

Example 14
FIG. 4 shows the pretilt in two different types of cells comprising an alignment layer that is a blend of polymers functionalized with VA and PA side groups described in Examples 1 and 3, respectively, as a function of the percentage of PA component. Present a corner. The cells were each filled with nematic liquid crystal materials MLC6873-100 (Δε> 0) and MLC6882 (Δε <0), both products of Merck. As can be seen, the pretilt angle is a decreasing function of the concentration of the PA compound.

Example 15
A cell was made according to the procedure described using 50%, 75% and 90% of the VA polymer, respectively, using the VA polymer from Example 4 mixed with the PA polymer from Example 6. The cell was also made using only PA polymer (corresponding to 0% VA) and 100% VA polymer. The results are shown in FIG. 5, which is a graph presenting the tilt angle as a function of VA content. As can be seen from this figure, the tilt angle increased as the content of the VA material in the mixture increased.
Thus, VA and PA materials can be mixed in different proportions to obtain different pretilt angles.
Optionally, the tilted (tilted) orientation is polymerized, for example, in a linear side group side chain polymer with side and end bonds, respectively, as schematically illustrated in FIG. 2c. It can be obtained by incorporation into the skeleton. This figure shows a side chain polymer containing both side groups with terminal bonds (VA) and side groups with side bonds (PA). The pretilt angle of such side chain polymers typically depends on the ratio of terminal linking groups to side linking groups.

  The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

Claims (23)

A composition for use in a surface-director alignment layer disposed between a confinement substrate of a liquid crystal device and a liquid crystal bulk material comprising:
The surface-director alignment layer causes liquid crystal molecules contained in the liquid crystal bulk material to form a desired pretilt angle with respect to the surface-director alignment layer in the absence of an applied electric field.
A first concentration of a first compound that, when used alone in the surface-director alignment layer, produces a first pretilt angle different from the desired tilt angle; and-in the surface-director alignment layer A homogeneous mixture comprising, when used alone, a second concentration of the second compound that produces a second pretilt angle different from the desired tilt angle and the first pretilt angle;
Here, the desired pretilt angle can be controlled by controlling at least one of the first and second concentrations. The composition according to claim 1, wherein the first pretilt angle is smaller than the desired tilt angle, and the second pretilt angle is larger than the desired tilt angle. The first pretilt angle is in the range of 0 ° to 45 °, preferably 5 to 25 ° with respect to the plane of the alignment layer, and the second pretilt angle is 45 ° with respect to the plane of the alignment layer. A composition according to claim 1 or 2, which is in the range of from 90 to 90, preferably from 70 to 85 °. 4. The composition of claim 3, wherein the first pretilt angle is substantially 0 ° and / or the second pretilt angle is substantially 90 °. The composition according to any one of claims 1 to 4, wherein at least one of the first and second compounds, preferably the second compound, produces the second pretilt angle by steric interaction. The composition according to any one of claims 1 to 5, wherein the first compound includes a first side group, and the second compound includes a second side group different from the first side chain group. The composition according to claim 6, wherein at least one of the first and second side groups exhibits shape anisotropy. At least one of the first and second side groups is selected from the group of molecules having an anisotropic shape such as linear, lath-like, disc-like, v-shape, bent-shape and bowl-shape. The composition according to claim 7. The composition according to any one of claims 6 to 8, wherein the first side group is bonded to the first repeating unit of the polymer skeleton, and the second side group is bonded to the second repeating unit of the polymer skeleton. object. The composition according to claim 9, wherein the first and second repeating units are repeating units having exactly the same polymer backbone. The composition of claim 9, wherein the first and second repeating units are repeating units of different polymer backbones. The composition according to any one of claims 8 to 11, wherein the first side group is bonded to the first repeating unit on a side surface. The composition according to any one of claims 8 to 12, wherein the second side group is mostly bonded to the second repeating unit at the terminal. The composition according to any one of claims 9 to 11, wherein the first side group and the second side group both have either a terminal bond or a side bond to the polymer backbone. The composition according to any one of claims 6 to 14, wherein at least one of the first and second side groups is an aromatic group. The composition according to any one of claims 7 to 15, wherein at least one of the first and second side groups is a mesogenic group. The at least one of the first compound and the second compound comprises a repeating unit functionalized with a pendant side chain selected from the group consisting of an optionally substituted alkyl group, an aryl group, and an alkylaryl group. The composition according to any one of 7 to 16. 18. At least one of said first and second compounds comprises a reactive, preferably photo-reactive side group and / or a photo-responsive side group. Composition. A surface director alignment layer material comprising the composition according to any one of claims 1 to 18 and an optional additional polymer. A liquid crystal device comprising: at least one confinement substrate; a liquid crystal bulk material; and a surface director alignment layer disposed in contact with a surface of the liquid crystal bulk material between the at least one confinement substrate and the liquid crystal bulk material, The liquid crystal device in which a surface director alignment layer contains the composition of any one of Claims 1 thru | or 18. -First and second confinement substrates sandwiching the liquid crystal bulk material;
A first surface director alignment layer disposed between the first confinement substrate and the liquid crystal bulk material in contact with a surface of the liquid crystal bulk material; and- between the first confinement substrate and the liquid crystal bulk material; A second surface director alignment layer disposed in contact with the surface of the liquid crystal bulk material;
A liquid crystal device comprising:
21. A liquid crystal device according to claim 20, wherein at least one, preferably both of the first and second surface director alignment layers comprises the composition according to any one of claims 1 to 18. The following steps:
-Preparing a confinement substrate;
Disposing a surface director alignment layer comprising a composition according to any one of claims 1 to 18 on the surface of the substrate; and-disposing a liquid crystal bulk material in contact with the alignment layer. The method for manufacturing a liquid crystal device according to claim 20, comprising a step. 23. The method of claim 22, wherein the step of disposing a surface director alignment layer comprises coating the surface with a prefabricated composition according to any one of claims 1-18.

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