WO2012100901A1

WO2012100901A1 - Device containing a liquid crystal medium

Info

Publication number: WO2012100901A1
Application number: PCT/EP2012/000023
Authority: WO
Inventors: Graziano Archetti
Original assignee: Merck Patent Gmbh
Priority date: 2011-01-27
Filing date: 2012-01-04
Publication date: 2012-08-02
Also published as: TWI600943B; DE102012000065A1; DE102012000065B4; TW201239458A

Abstract

The invention relates to a temperature-reactive device for regulating light transmission, containing a liquid crystal medium and a component (N) containing nanoparticles and/or one or more compounds (V) with a three-dimensional structure. The invention further relates to a method for the temperature-dependent control of light transmission through a layer of a liquid crystal medium.

Description

Device containing a liquid-crystalline medium

The present invention relates to a temperature-responsive device for regulating the light transmission, comprising a liquid-crystalline medium and a component (N) containing nanoparticles and / or one or more compounds (V) with a three-dimensional structure. Furthermore, the invention relates to a method for temperature-dependent control of the light transmission through a layer of a liquid-crystalline medium.

In the context of the present invention, the term liquid-crystalline medium is understood as meaning a material which exhibits liquid-crystalline properties under certain conditions. In particular, the term is understood to mean a material which under certain

Conditions forms a nematic liquid-crystalline phase. A liquid-crystalline medium can be one or more liquid-crystalline

Compounds and additionally include other substances.

The term liquid-crystalline compound is understood as meaning a compound which under certain conditions is liquid-crystalline

Properties shows, and in particular a compound which forms a nematic liquid-crystalline phase under certain conditions.

In the context of the present application, a temperature-reactive device is understood to mean a device which assumes different states depending on the temperature. An example of this is a device which, depending on the temperature, exhibits a different level of light transmission.

In the context of the present application, the term light transmission is understood to mean the passage of electromagnetic radiation in the visible (VIS), in the near-infrared (near-IR, NIR) and in the UV-A range through the device. In the present application, the term light is likewise understood to mean electromagnetic radiation in the visible, near-infrared and UV-A region of the spectrum. According to commonly used physical definitions is under UV-A light, visible light and near-infrared light taken together radiation of a wavelength of 320 to 3000 nm understood.

In the context of the present application, the term nanoparticles is understood to mean a particle having a diameter of between 1 nm and 1 μm.

Under the term connection with three-dimensional structure becomes in the

In the context of the present invention, a compound is understood which is not predominantly linear and extended in only one dimension, for example a polymer or a small organic molecule, such as, for example, octa-1, 7-diyne, n-decane or p-quaterphenyl, and which, furthermore, is not predominantly planar and extended in only two dimensions, such as benzene or pyrene, but which has a substantially uniform expansion in all three dimensions of the space. Examples of such compounds are tetraphenylmethane, cubane, closo-carbaboranes such as C2B ₀ Hi ₂ , fullerenes and silsesquioxanes. Generally, molecular cage compounds, as defined in a following section, typically represent compounds of three-dimensional construction as defined above. For example, a compound having a three-dimensional structure may be approximated

have spherical, cube-shaped, tetrahedral or pyramidal structure.

Such a compound preferably has a longitudinal extent d _max and a further linear length d _min , where d _{max is} defined as the greatest extent and d _m i _{n is} defined as the smallest extent, and where d _{m is} at least 30% of the value of d _max , more preferably at least 50%, even more preferably at least 70%, and most preferably at least 80% of the value of d _max .

The determination of the mentioned structural parameters can be done by the

Skilled conventional simulation method for the spatial structure of compounds. These generally have sufficient accuracy to allow a person skilled in the art to classify a compound as a three-dimensional construction according to the above To enable definition. Furthermore, the person skilled in the art, in particular in the case of novel and / or lesser-known structural classes, can refer to the

Structure determination by crystallography or spectroscopic

Resort to methods. With the increasing importance of energy efficiency of buildings there is a growing demand for devices which control the passage of light and thus the flow of energy through windows or glass surfaces.

In particular, there is a need for devices which control the flow of energy through glass surfaces to those prevailing at the time

Conditions (heat, cold, high insolation, low

Sunlight). Of particular interest is the provision of such devices in temperate climates, where a seasonal change of warm outdoor temperatures combined with high solar radiation and cold outdoor temperatures combined with low solar radiation occurs.

The following are the effects to be presented by

Solar radiation on glass surfaces on buildings caused.

Similar effects can occur not only in buildings, but also in vehicles or transport containers, for example containers.

In warm climates and in temperate climates in the warmer months, glass surfaces on buildings lead to an undesirable

Heating the interiors when they are struck by sunlight. This is because glass is permeable to radiation in the VIS and near IR regions of the electromagnetic spectrum. Objects in the interior absorb the transmitted radiation and are thereby heated, resulting in an increase in the room temperature

(Greenhouse effect, green house effect). However, the mentioned effect of glass surfaces on buildings is not generally undesirable: at low levels

Outside temperatures, especially in cold climates or in the cold season in temperate climates, heating of the interior due to solar radiation in the context of this effect may be advantageous because it reduces the energy requirements for space heating and thus costs can be saved. It is therefore the technical task to provide devices which the passage of light through windows or other glass surfaces

regulate. In particular, the task arises, devices

be provided, which automatically adjust the regulation of the passage of light to the prevailing conditions, as shown above (smart

Windows). Furthermore, the task of providing devices which operate preferably energy-efficient, with the least possible

technical effort can be installed, are technically reliable and meet aesthetic requirements. As examples of the latter aspect, as regular as possible switching of the device and avoidance of color or pattern effects should be mentioned.

Known in the prior art are devices which, when an electrical voltage is applied, reversibly change from a transparent state to a less transparent one, for example a cloudy one

(light scattering) or a dark transparent state (e.g., C.M. Lampert et al., Solar Energy Materials & Solar Cells, 2003, 489-499). However, electrically switchable devices such as the above devices have the disadvantage that they are not directly and

automatically adapt to the ambient conditions. Furthermore, they require electrical connections, resulting in increased installation costs and increased maintenance requirements.

US 2009/0015902 and US 2009/0167971 disclose temperature-responsive devices containing a liquid crystalline medium in a layer between two polarizers. In this case, the switching between a state with a higher light transmission and a state with a lower light transmission through a phase transition of the

liquid crystalline medium reaches from a nematic state to an isotropic state. In this case occurs due to the phase transition on an abrupt transition between the state with high and the state with less light transmission. In this case, the case may occur that viewed over the entire surface of the device in some areas High-transmission state, while in others,

adjacent areas at the same time the condition with lower

Light transmission is present.

It can be summarized that there continues to be a need for temperature-responsive devices for regulating the passage of light through windows or generally translucent surfaces.

In particular, there is a need for devices in which the switching process is based on alternative principles. Again, in particular, there is a need for devices in which the switching process does not take place abruptly but gradually over intermediate values of the transmission.

In S.-C. Jeng et al., Optics Letters 2009, 34, 455-457, discloses that certain liquid crystalline compounds may be present in the presence of

align spontaneously homeotropically (vertically) to polyhedral oligomeric silsesquioxanes (silsesquioxanes, PSS). The degree of vertical alignment can be influenced by the concentration of silsesquioxanes.

Furthermore, a use of the mixtures containing liquid crystalline compounds and silsesquioxanes in LC displays based on the VA technology (VA technology = ertical alignment) is disclosed in which by applying an electric field, a reversible rotation of the

liquid crystalline compounds out of the vertical arrangement takes place. Comparable applications are further described in US 2008/0198301 and in S.-C. Jeng et al., Appl. Phys. Lett. 2007, 91, 0611121 - 0611123. The present invention is the use of a liquid-crystalline medium containing

- One or more liquid crystalline compounds as well

a component (N) containing nanoparticles and / or one or more

several compounds (V) which have a three-dimensional structure and a molecular weight of more than 450 Da,

in a temperature-reactive switching element.

The subject matter of the present invention is thus furthermore a temperature-responsive device for regulating the light transmission in that it contains a layer of a liquid-crystalline medium, the liquid-crystalline medium

- One or more liquid crystalline compounds as well

a component (N) containing nanoparticles and / or one or more

several compounds (V) with a three-dimensional structure and a molecular weight of more than 450 Da,

contains.

In a preferred embodiment of the invention, the ^'layer of the liquid crystalline medium between two substrate layers is arranged.

According to the invention, the substrate layers may consist inter alia of polymeric material, of metal oxide, for example ITO, of glass or of metal. Preferably, they are made of glass or ITO. In a preferred embodiment, the substrates are arranged at a distance of at least 1 [1 to one another, with the layer of the liquid-crystalline medium being located in the intermediate space. The substrate layers can be kept at a defined distance from each other, for example, by spacers or projecting structures in the layer.

The device may further comprise one or more orientation layers which are in direct contact with the layer of the liquid-crystalline medium. The orientation layers may also serve as substrate layers, so that no substrate layers are required in the device. If additional substrate layers are present, then the orientation layers are each arranged between the substrate layer and the layer of the liquid-crystalline medium. In a preferred embodiment of the invention, the orientation layers are made of rubbed polyimide. Methods for rubbing the polyimide are known in the art, so that they are not explicitly listed here. In an alternative embodiment of the invention, the alignment layers are made of non-rubbed polyimide. Rubbed polyimide favors preferential alignment of the non-rubbed polyimide of the liquid crystalline compounds in the rubbing direction when the compounds are planar to the alignment layer. It is according to the present invention also possible and advantageous under certain conditions that the device no

Orientation layers adjacent to the layer of the liquid-crystalline medium.

In a preferred embodiment of the invention, the device comprises two or more polarizers, one of which on one side of the layer of the liquid-crystalline medium and another on the

opposite side of the layer of the liquid-crystalline medium is arranged. In this case, the layer of the liquid-crystalline medium and the polarizers are preferably arranged parallel to one another.

The polarizers can be linear polarizers or circular polarizers. Preferably, exactly two polarizers are present in the device. In this case, it is further preferred that the polarizers represent either both linear polarizers or both circular polarizers. However, according to a possible embodiment of the invention, a linear polarizer may also be used together with a circular polarizer

Polarizer can be used.

If two linear polarizers are present in the device, then it is preferred according to the invention that the polarization directions of the two polarizers are rotated the same or only by a small angle relative to one another.

Furthermore, it is in the case that two circular polarizers in the

Device are present, it is preferred that they are the same

Have polarization, that is, either both right circular or both left are circularly polarized.

The polarizers can be reflective or absorptive polarizers. A reflective polarizer in the context of the present application reflects light of one polarization direction or one type of circularly polarized light, while it is transparent to light of the other polarization direction or the other type of circularly polarized light. Corresponding An absorptive polarizer absorbs light of one polarization direction or type of circularly polarized light while being transparent to light of the other polarization direction or the other type of circularly polarized light. The reflection or absorption is usually not quantitative, so that there is no complete polarization of the light passing through the polarizer.

In the context of the present invention, both absorptive and reflective polarizers can be used. It is preferred to use polarizers which are present as thin optical films. Examples of reflective polarizers which can be used in the device of the invention are DRPF (diffuse reflective polarizer film, 3M), DBEF (dual brightness enhanced film, 3M), DBR (layered polymer distributed Bragg reflectors, as disclosed in US Pat 7,038,745 and US 6,099,758) and APF (Advanced Polariser Film, 3M) films. Furthermore, polarizers based on wire gratings (WGP, wire-grid polarisers) which reflect infrared light may be used. Examples of absorptive polarizers which can be used in the devices according to the invention are the Itos XP38 polarizer film and the Nitto Denko GU-1220DUN polarizer film. An example of a circular polarizer which can be used in the present invention is the polarizer APNCP37-035-STD (American Polarizers). Another example is the polarizer CP42 (ITOS).

In one embodiment of the invention, the polarizers represent the substrate layers between which the liquid-crystalline medium is disposed, that is, there are no additional substrate layers present in the device.

In a further preferred embodiment of the invention, the layer of the liquid-crystalline medium is located between flexible layers, for example flexible polymer films. The device according to the invention is thus flexible and flexible and can be rolled up, for example. The flexible layers may optionally be substrate layer, alignment layer and / or polarizers. Other layers, which are preferably also flexible, may additionally be present. For more advanced Disclosure of preferred embodiments in which the layer of liquid-crystalline medium is sandwiched between flexible layers is referred to the application US 2010/0045924.

In a further preferred embodiment of the invention, the liquid-crystalline medium has a solid or gel-like consistency. As a result, the device according to the invention is less susceptible to

Damage. Furthermore, in addition to the layer of the liquid-crystalline medium, only flexible, bendable and cuttable layers are used

present, the device can not only be rolled up, but it can also cut out pieces of a required area.

The device may further include filters which block light of certain wavelengths, for example UV filters. It can

According to the invention, further functional layers may be present, such as, for example, protective films, heat-insulating films or metal-oxide layers.

Furthermore, electrodes and other electrical components and connections may be present in the device according to the invention in order to enable an electrical switching of the device, comparable to the switching of an LC display. In a preferred embodiment of the invention, however, electrodes and other electrical components and connections are not present. Furthermore, it is generally preferred in use of the device that the switching be effected by a change in temperature (and not by the application of an electric field). preferred

Temperature ranges of the switching operation will be explained later

Specified sections.

According to the invention, component (N) contains nanoparticles and / or one or more compounds (V) with a three-dimensional structure and a molecular weight of more than 450 Da. Component (N) is dissolved or dispersed in the liquid-crystalline medium according to the invention. Preferably, the component (N) is in

liquid-crystalline medium dispersed.

The component (N) is preferably chemically inert, resistant to aging and lipophilic and with those contained in the liquid-crystalline medium

liquid crystalline compounds compatible. In the context of the present invention, compatibility is understood in particular to mean that component (N) with the compounds does not undergo any chemical reactions which impair the functioning of the device.

The component (N) is preferably used in a concentration of 50 to 0.01 wt .-%, more preferably 30 to 0.1 wt .-% and most preferably 10 to 0.1 wt .-% in the liquid-crystalline medium. Even more preferably, the concentration of component (N) is between 5 and 0.1% by weight.

In a preferred embodiment of the invention, component (N) contains nanoparticles. In a preferred embodiment, the

Component (N) Nanoparticles in an amount of 50, 70, 90 or more wt .-%. Most preferably, component (N) consists entirely of nanoparticles. The nanoparticles may be, for example, metal nanoparticles, metal oxide nanoparticles or clusters.

The nanoparticles preferably have a diameter of 1 nm to 00 nm, more preferably a diameter of 1 nm to 50 nm, more preferably 1 nm to 10 nm and even more preferably 1 nm to 5 nm. It is further preferred that the Particles have an aspect ratio dmax min of at most 3: 1, preferably at most 2: 1, possess. D _max denotes the maximum length expansion and d _m j _n the minimum longitudinal extent of the particle. The size and shape of the nanoparticles can be determined, for example, by scattering methods in solution or by transmission electron microscopy (TEM).

The nanoparticles used may be the same or different in shape, size and structure. In a preferred embodiment of the invention, the nanoparticles have at least one anchor group A ¹ . This preferably represents an organic chemical group. Further preferably, the anchor group A ^{1 represents} a group which enters into a non-covalent interaction with surfaces of glass or metal oxide. Such a surface can

for example, be the surface of the substrate layer of the device.

In a preferred embodiment, the anchor group A ¹ is constructed so that it can form a hydrogen bond via polar structural elements. Suitable groups include polar groups

Groups of atoms selected from N, O, S, and P, which are preferably simultaneously stable to air and water. Preferably, one or more, preferably two or more, of these heteroatoms in the anchor group A ^{1 are} included.

The anchor group A ¹ particularly preferably consists of at least two separate structural elements which contain heteroatoms selected from N and O, wherein N is preferred, as well as further comprising at least one covalent linking structure between said

Structural elements and optionally between one or more of

Structural elements and the attachment point of the anchor group A.

Said covalent structure consists of chain-like or cyclic aliphatic radicals and / or aromatic rings, preferably of saturated hydrocarbon chains and / or aliphatic rings.

Aliphatic rings include, for example, cyclohexane and cyclopentane.

The anchor group A ¹ preferably represents a group of the following formula (A-)

wherein each independently

E represents a single bond or any spacer group; X ^{1 is} selected from -NH-, -NR ¹ -, -O- and a single bond;

X ^{2 is} selected from -NH ₂ , -NHR, NR _2> -OR ¹ and -OH;

Z ^{1 is} selected from an alkylene group having 1-15 C atoms, a carbocyclic ring group having 5 or 6 C atoms, or

Combinations of such groups wherein the groups may each be substituted by OH, OR ¹ , -NH ₂ , -NHR ¹ , -NR ¹ 2, or halogen;

R is the same or different at each occurrence selected from H, D, or an aliphatic, aromatic and / or

heteroaromatic organic radical having 1 to 30 carbon atoms, in which also one or more H atoms may be replaced by D or F; a is 0, 1, 2 or 3, preferably 1 or 2, especially

preferably 1; and

* marks the attachment point of the anchor group.

The general designations for organic radicals used in the present application are explained below. The specific embodiments listed are according to the invention

prefers.

An aryl group in the sense of this invention contains 6 to 60 C atoms; a heteroaryl group in the context of this invention contains 1 to 60 carbon atoms and at least one heteroatom, with the proviso that the sum of

C atoms and heteroatoms at least 5 yields. The heteroatoms are preferably selected from N, O and / or S.

In this case, an aryl group or heteroaryl group is either a simple aromatic cycle, ie benzene, or a simpler one

heteroaromatic cycle, for example pyridine, pyrimidine or thiophene, or a fused (fused) aromatic or heteroaromatic polycycle, for example naphthalene, phenanthrene, quinoline or carbazole understood. A condensed (anneliierter) aromatic or heteroaromatic polycycle is in the sense of the present

Significance of two or more condensed simple aromatic or heteroaromatic cycles.

An aryl or heteroaryl group which may optionally be substituted by the abovementioned groups is understood in particular to mean groups which are derived from benzene, naphthalene, anthracene, phenanthrene, pyrene, dihydropyrene, chrysene, perylene, fluoranthene, benzanthracene and benzphenanthrene , Tetracene, pentacene, benzopyrene, furan, benzofuran, isobenzofuran, dibenzofuran, thiophene, benzothiophene,

Isobenzothiophene, dibenzothiophene, pyrrole, indole, isoindole, carbazole, pyridine, quinoline, isoquinoline, acridine, phenanthridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline, phenothiazine, phenoxazine, Pyrazole, indazole, imidazole, benzimidazole, naphthimidazole, phenanthrimidazole, pyridimidazole, pyrazine imidazole, quinoxalinimidazole, oxazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, 1, 2-thiazole, 1, 3-thiazole, benzothiazole, pyridazine, benzopyridazine, Pyrimidine, benzpyrimidine, quinoxaline, pyrazine, phenazine, naphthyridine, azacarbazole, benzocarboline, phenanthroline, 1, 2,3-triazole, 1, 2,4-triazole, benzotriazole, 1, 2,3-oxadiazole, 1, 2,4- Oxadiazole, 1, 2,5-oxadiazole, 1, 3,4-oxadiazole, 1,2,3-thiadiazole, 1, 2,4-thiadiazole, 1, 2,5-thiadiazole, 1, 3,4-thiadiazole, 1, 3,5-triazine, 1, 2,4-triazine, 1, 2,3-triazine,

Tetrazole, 1, 2,4,5-tetrazine, 1,2,3,4-tetrazine, 1, 2,3,5-tetrazine, purine, pteridine, indolizine and benzothiadiazole.

In the context of the present invention, among an alkyl, alkenyl or alkynyl group, which may optionally be substituted, are preferably the radicals methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t Butyl, 2-methylbutyl, n-pentyl, s-pentyl, cyclopentyl, neo-pentyl, n-hexyl, cyclohexyl, neo-hexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, trifluoromethyl , Pentafluoroethyl, 2,2,2-trifluoroethyl, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl,

Octenyl, cyclooctenyl, ethynyl, propynyl, butynyl, pentynyl, hexynyl or octynyl understood. Under an optionally substituted alkyloxy, alkylthio,

Alkenyloxy, alkenylthio, alkynyloxy and alkynylthio groups are preferably methoxy, trifluoromethoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy, n-pentoxy, s-pentoxy, 2-methylbutoxy, n-hexoxy, Cyclohexyloxy, n-heptoxy, cycloheptyloxy, n-octyloxy, cyclooctyloxy, 2-ethylhexyloxy, pentafluoroethoxy, 2,2,2-trifluoroethoxy, methylthio, ethylthio, n-propylthio, i-propylthio, n-butylthio, i-butylthio, s- Butylthio, t-butylthio, n-pentylthio, s-pentylthio, n-hexylthio, cyclohexylthio, n-heptylthio,

Cycloheptylthio, n-octylthio, cyclooctylthio, 2-ethylhexylthio,

Trifluoromethylthio, pentafluoroethylthio, 2,2,2-trifluoroethylthio, ethenylthio, propenylthio, butenylthio, pentenylthio, cyclopentenylthio, hexenylthio, cyclohexenylthio, heptenylthio, cycloheptenylthio, octenylthio,

Cyclooctenylthio, ethynylthio, propynylthio, butynylthio, pentynylthio,

Hexinylthio, heptynylthio or octynylthio understood.

In a preferred embodiment of the invention, the group E represents a single bond or a spacer group selected from a

Alkylene group having 1 to 20 carbon atoms, which is optionally substituted by radicals selected from F, Cl, Br, I and CN, wherein one or more CH ₂ groups in the alkylene group each independently

-O-, -S-, -NH-, -N (R ¹ ) -, -Si ((R) ₂ ) -, -CO-, -CO-O-, -O-CO-, -O-CO -O-, -S-CO-, -CO-S-, -N (R ¹ ) -CO-O-, -O-CO-N (R ¹ ) -, -N (R ¹ ) -CO-N (R ¹ ) -, -CH = CH- or -CsC- may be replaced. More preferably, E represents a single bond or a group selected from - (CH ₂ ) _b -, - (CH ₂ ) _b -O-, - (CH ₂ ) _b -O-CO- and - (CH ₂ ) _b -O- CO-O-, where b is an integer from 1 to 20, preferably from 1 to 10.

R ¹ is preferably selected from an optionally substituted with D and / or halogen alkyl or alkoxy group having 1 to 15 carbon atoms or an optionally substituted with D and / or halogen alkenyl, alkynyl,

Alkenyloxy or alkynyloxy group having 2 to 15 carbon atoms and an optionally substituted with D and / or halogen aryl or heteroaryl group having 5 to 18 aromatic ring atoms and combinations of said groups.

R ¹ is particularly preferably selected from an alkyl or alkenyl group having at most 15 C atoms, which is optionally substituted by D, phenyl and / or halogen. Particularly preferably, the anchor group A ^{1 represents} a group of the following formula (A-2)

wherein E, X ¹ , X ² and R ^{1 are} as defined above and c has a value of 1 to 10, preferably from 1 to 5, particularly preferably from 1 to 3. R ¹ is preferably selected from the preferred groups listed above.

In a further preferred embodiment of the invention, the nanoparticles have no anchor groups A ¹ . In this case, they are preferably functionalized with other chemical groups, which are preferably non-polar, for example optionally substituted alkyl, alkyloxy, alkylthio, alkenyl, alkenyloxy, alkenylthio, alkynyl, alkynyloxy, alkynylthio, aryl, aryloxy , Arylthio, aralkyl, heteroaryl, heteroaryloxy, heteroarylthio and heteroaralkyl groups. The groups preferably have at most 20 C atoms, more preferably at most 10 C atoms.

In a further preferred embodiment of the invention, component (N) contains one or more compounds (V) with a three-dimensional structure and a molecular weight of more than 450 Da. In a preferred embodiment of the invention, the molecular weight of the compounds (V) is more than 500 Da, more preferably more than 600 Da and most preferably more than 700 Da. Preferably, the compounds (V) are molecular compounds. Further preferred are, inter alia, the preferred embodiments given above in the definition of the term "compound having a three-dimensional structure" concerning the ratio of maximum to minimum expansion of the compounds.

In a preferred embodiment, the compounds (V) have one or more anchor groups A ¹ . In a preferred embodiment of the invention component (N) contains a single compound (V). In an alternative, likewise preferred embodiment of the invention, component (N) contains a plurality of different compounds (V), preferably 2, 3, 4 or 5, more preferably 2 or 3 different compounds (V).

More preferably, the compound (V) is a molecular one

Caged connection dar. Alternatively, the compound but also a

represent tetrasubstituiertes methane derivative.

In a preferred embodiment of the invention, therefore, the device contains a component (N) which contains one or more compounds (V) with a three-dimensional structure and a molecular weight of more than 450 Da, which represent molecular cage compounds.

In the context of the present application, a molecular cage compound is understood as meaning a polycyclic molecular compound whose atoms and chemical bonds form a three-dimensional closed framework (cage).

In a particularly preferred embodiment of the invention, the molecular cage compound provides a fullerene derivative, a borane derivative

Carbaboran derivative, a silsesquioxane derivative, a cubane derivative or a Tetrahedranderivat. Most preferably, the molecular cage compound is a silsesquioxane derivative.

In a particularly preferred embodiment of the invention, therefore, the device contains a component (N) which contains one or more

Compounds (V) with a three-dimensional structure and a

Molecular weight of more than 450 Da, which represent silsesquioxane derivatives.

Preferred silsesquioxane derivatives according to the present invention have the general structure N-1:

in which

R is the same or different at each instance and represents an anchor group A or a radical R ¹ which, as defined above, is identically or differently selected on each occurrence from H, D, or an aliphatic, aromatic and / or heteroaromatic organic radical having 1 to 30 C atoms, in which also one or more H atoms can be replaced by D or F.

One, two or three groups R preferably represent an anchor group A ^1. Particularly preferably, one or two groups R, and very particularly preferably exactly one group R, represents an anchor group A ¹ .

The anchor groups A ¹ are as defined above. Preferred are the

Anchor groups A ¹ selected from the preferred embodiments given above.

If a metal oxide layer, for example ITO, or a glass layer is used as the substrate layer, at least one anchor group A ¹ is preferably present which contains N and / or O atoms, for example as

Components of an amino, hydroxyl and / or ether group.

If the substrate layer is a polymer layer, preferably polyimide,

is used, preferably at least one anchor group A ^{1 is} present, which contains N atoms, for example in an amino group.

However, it may also be preferred according to the invention that none

Anchor group A ^{1 is present} in the compounds. Furthermore, R ^{1 is} preferably selected from an optionally substituted with D and / or halogen alkyl or alkoxy group having 1 to 15 carbon atoms or an optionally substituted with D and / or halogen alkenyl, alkynyl, alkenyloxy or alkynyloxy group with 2 to 15 C atoms or an optionally substituted with D and / or halogen aryl or heteroaryl group having 5 to 18 aromatic ring atoms or combinations of said groups.

R ¹ is particularly preferably selected from an alkyl or alkenyl group having at most 15 C atoms, which is optionally substituted by D, phenyl and / or halogen.

Particularly preferred embodiments of the molecular

Cage compounds for use according to the invention are those in

Silsesquioxane derivatives listed below.

Further examples of molecular cage compounds according to the present invention are dimers or oligomers of silsesquioxanes functionalized on each silsesquioxane moiety by an anchor group. Several silsesquioxane units can be connected via the attached to the corners of organic radicals to dimers or oligomers.

The liquid-crystalline medium according to the present invention comprises one or more, preferably a plurality of liquid-crystalline compounds and optionally further compounds, for example stabilizers and / or chiral dopants. Such compounds are known to the person skilled in the art. They are preferably used in a concentration of 0% to 30%, more preferably 0.1% to 20% and most preferably 0.1% to 10%.

In the liquid-crystalline medium according to the invention preferably at least 3, more preferably at least 4 and most preferably at least 5 different liquid crystalline compounds are used. The liquid-crystalline medium can according to the invention a positive

have dielectric anisotropy Δε. In this case, Δε preferably has a value of> 1.5.

The liquid-crystalline medium may according to the invention have a negative dielectric anisotropy Δε. In this case, Δε preferably has a value of -1.5.

According to the invention, the liquid-crystalline medium may also have an amount of small positive or negative dielectric anisotropy Δε. In this case, Δε is preferably: -1.5 <Δε <1.5. Such

Liquid-crystalline medium is also the subject of the present invention

Invention. Particularly preferred in this case is -1.0 <Δε <1.0

The liquid-crystalline medium preferably has a nematic phase in a temperature range from 0 ° C to 50 ° C. More preferably, the liquid crystalline medium has a nematic phase in a range of -20 ° C to 80 ° C, even more preferably in a range of -40 ° C to 100 ° C.

The liquid-crystalline medium can according to the invention any

contain liquid crystalline compounds.

One or more are preferred in the liquid-crystalline medium

Compounds of the following formula (F-1) included

in which

R ¹¹ , R ^{12 are the} same or different at each occurrence F, Cl, -CN, -NCS,

-SCN, R ³ -O-CO-, R ¹³ -CO-O- or an alkyl or alkoxy group having 1 to 10 carbon atoms or an alkenyl or alkenyloxy group having 2 to 10 carbon atoms, wherein a or more hydrogen atoms in the above-mentioned groups may be replaced by F or Cl, and one or more CH ₂ groups may be replaced by O or S; and R ^{13 represents,} identically or differently, an alkyl group having 1 to 10 C atoms in each occurrence, in which one or more hydrogen atoms may be replaced by F or Cl, and one or more CH ₂ groups have been replaced by O or S. can; and

every occurrence is selected the same or different

wherein each occurrence is identically or differently selected from F, Cl, CN or an alkyl, alkoxy or alkylthio group having 1 to 10 C atoms, wherein one or more hydrogen atoms in the abovementioned groups may be replaced by F or Cl, and wherein one or more CH ₂ groups in the above groups can be replaced by O or S; and Z ^{11 is the} same or different at each occurrence

-CO-O-, -O-CO-, -CF ₂ -CF ₂ -, -CF ₂ -O-, -O-CF ₂ -, -CH ₂ -CH ₂ -, -CH = CH-, -CF = CF-, -CF = CH-, -CH = CF-, -C ^ C-, -OCH ₂ -, -CH ₂ O-, and a single bond; and d has a value of 0, 1, 2, 3, 4, 5 or 6, preferably 0, 1, 2 or 3, more preferably 1, 2 or 3.

For the sake of clarity, it should be noted that groups

can be the same or different at every occurrence.

Particularly preferred embodiments of the liquid-crystalline

Compounds for use in the device according to the invention correspond to the formulas disclosed in Tables A and B below.

How the devices according to the invention are produced is known to the person skilled in the art in the field of devices comprising liquid-crystalline media.

In particular, the liquid-crystalline medium containing

- One or more liquid crystalline compounds as well

a component (N) containing nanoparticles and / or one or more

several compounds (V) with a three-dimensional structure and a molecular weight of at least 450 Da,

applied in a layer on a substrate layer. The application preferably takes place in a layer between two substrate layers. According to the invention, it may be necessary to have a heating and / or

Cooling step to obtain an initial homeotropic alignment of the liquid crystalline compounds.

For the preparation of the liquid-crystalline medium, the component (N) is dissolved or dispersed in the liquid-crystalline compound or the mixture containing the liquid-crystalline compound.

In the following, the principle of operation of the device according to the invention will be explained in more detail. It is noted that it is not intended to derive any limitation on the scope of the claimed invention from the statements to the presumed operation, which are not in the

Claims is included.

The device according to the invention has a light transmission

(Transmission), which depends on the temperature. In a preferred embodiment, its translucency is high at low temperature and low at high temperature.

In a preferred embodiment, the inventive

Device on a limit state A and a limit state B on. In the context of the present application, the term limit state is understood to mean a state in which the transmission reaches a maximum or a minimum value and does not change or hardly changes any further when the temperature is lowered further or increased. However, this does not preclude a further change in the transmission in the event of a sharp reduction or increase in the temperature beyond the temperature of the limit state.

Preferably, the device has a limit state A with a

Transmission TA at a temperature less than a limit temperature Θ _Α on, and a limit state B with a transmission TB at a temperature greater than a limit temperature ΘΒ, where:

Preferably, Θ _{Α is} between -15 and +25 ° C, more preferably between -5 and +10 ° C.

Preferably, ΘΒ is between +60 and +100 ° C, more preferably between +70 and +90 ° C.

The temperature range between the two limit temperatures 0 _A and Θ _Β represents the range in which the device reacts to changes in temperature with a change in the transmission (working range or switching range of the device). The device is preferably used at temperatures within this range. However, it can also be used at temperatures outside this range, preferably at

Temperatures below Θ _Α . The working range of the device according to the invention can be adjusted and changed so that the concentration of

Component (N) and / or the composition of the liquid-crystalline mixture is varied. Furthermore, the working range of the device according to the invention can be adjusted and changed by varying the substrate material.

Preferably, the switching range of the device is at room temperature and above. Particularly preferred values for the span between the

Limit temperatures Θ _Α and Θ _Β and thus for the switching range of

Device are:

0 ° C to 100 ° C; more preferably 5 ° C to 80 ° C; even more preferably 20 ° C to 60 ° C.

According to the invention, the transition between the two runs

Limit states A and B with increasing temperature as well as the transition between the two limit states B and A with decreasing temperature gradually over intermediate values of the transmission T.

According to the present invention, the liquid crystalline compounds are at low temperature to a large extent vertical to

Substrate surface aligned (homeotropic alignment). With rising

Temperature decreases the proportion of vertically aligned compounds. From a certain temperature, the value of which depends on the component (N) used and the composition of the liquid-crystalline medium and the nature of the substrate material, the compounds are planar to

Aligned substrate surface. The liquid-crystalline ones are preferred

Links in the state A of the switching element for the most part homeotropically aligned and in the state B of the switching element for

predominantly planar aligned. The change from homeotropic to planar alignment of the liquid-crystalline compounds can be used to achieve a temperature-dependent change in the transmission of the device.

The subject matter of the present invention is thus also a method for the temperature-dependent control of the light transmission by means of a

Device comprising a layer of a liquid-crystalline medium, characterized in that the liquid-crystalline medium

- One or more liquid crystalline compounds as well

a component (N) containing nanoparticles and / or one or more

several compounds (V) with three-dimensional structure and a

Molecular weight of at least 450 Da,

contains, and the liquid crystalline compounds change temperature depending on a homeotropic orientation to a planar orientation. In this method, a polarizer is preferably present on one side of the layer of the liquid-crystalline medium and on the opposite side of the layer of the liquid-crystalline medium. Preferred embodiments of polarizers have been described in a previous section. An example is to illustrate how such a method can be performed. At the same time, the example also shows a preferred embodiment of the device according to the invention. In this example, a linear polarizer is present on one side of the layer of the liquid-crystalline medium. On the opposite side of the layer of the liquid-crystalline medium, a further linear polarizer is present whose polarization plane is aligned the same as the polarization plane of the first linear polarizer. For homeotropic alignment of the

liquid crystalline compounds in the layer of liquid crystalline

Medium thus enters the light, which passes through the first polarizer, and through the second polarizer. This corresponds to the

Limit state A with high transmission T _A , as defined above. With planar alignment of the liquid crystalline compounds in the layer of

liquid-crystalline medium, however, the polarization properties of the light passing through the first polarizer are changed as it passes through the layer of the liquid-crystalline medium. This results in the light being partially or completely blocked by the second polarizer, i. H. absorbed or reflected. This condition corresponds to the

Limit state B with low transmission T _B , as defined above. At intermediate values of the temperature between the temperatures of the

Limit states A and B achieve values for the transmission which lie between those of the values for the transmission at the limit states A and B.

The device according to the present invention can be attached to windows, transparent facades, doors or roofs.

The invention thus also relates to the use of

Device according to the invention for regulating the light entry and / or the energy input into an interior space.

The invention further relates to the use of a

containing liquid-crystalline medium

- One or more liquid crystalline compounds as well a component (N) containing nanoparticles and / or one or more compounds (V) with a three-dimensional structure and a molecular weight of at least 450 Da,

for temperature - dependent regulation of light transmission from the

Surroundings in a circumscribed space.

As mentioned above, the invention is not limited to buildings, but can also be applied in transport containers, for example, containers or vehicles. It is particularly preferred to the device

To install glass panes of windows or to use them as a component of multi-pane insulating glass. The device according to the invention can be mounted on the outside, the inside or in multi-pane glass in the space between two glass panes, wherein the inside is the side of a glass surface, which is directed to the interior. Preferred is the use on the inside or in the space between two glass panes in multi-pane insulating glass.

The device according to the invention can completely cover the respective glass surface on which it is mounted or only partially cover it. With complete coverage, the influence on the light passage through the

Glass surface maximum. By contrast, in the case of partial coverage, even in the state of the device with low transmission, there is a certain transparency of the glass surface through the uncovered parts. Partially

Cover, for example, can be realized by mounting the devices in the form of stripes or specific patterns on the glass surface.

In a preferred embodiment of the invention, the device automatically regulates the passage of light through the glass surface into the interior, solely due to its temperature reactivity. No manual regulation is required.

According to this preferred embodiment, the device contains no electrodes or other electronic components with which an electrical switching of the device could take place. In an alternative embodiment of the invention, the device also has an electrical in addition to its Temperaturschaltbarkeit

Switchability on. In particular, in this case, electrodes are present in the device, and the liquid-crystalline medium has a positive or negative dielectric anisotropy Δε. It is preferred that Δε> 1.5 or that Δε <-1.5. In this embodiment of the invention, a manual, electrically switched switching of the device from high transmission to low transmission and vice versa is possible. How such an electrical switching of a liquid crystalline medium from a homeotropic state to another state can be achieved is known to those skilled in the art of containing

Liquid-crystalline media known.

Preferred liquid crystalline compounds according to the present invention

Invention are listed in the following Tables A and B.

In the following, the structures of the liquid-crystalline compounds are indicated by acronyms, wherein the transformation into chemical formulas takes place according to Tables A and B below. All radicals C _n H _{2n +} i and C _m H _{2m + 1} are straight-chain alkyl radicals with n or m C atoms; n, m, z and k are integers and are preferably 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12.

In Table A, only the acronym for the main body is given. in the

An individual case is followed by a prime for the parent with a dash followed by a code for the substituents R ^r , R ^{2 *} , L, and L ^{2 *} :

Table B

n, m, z are independently of one another preferably 1, 2, 3, 4, 5 or 6.

The following Table C indicates stabilizers which are preferably used in the liquid-crystalline media according to the invention.

Table C

Note: n is an integer from 1 to 12 in this table.



Unless otherwise stated, in the present application all concentrations are given in weight percent and refer to the corresponding total mixture containing all solid or

liquid crystalline components, without solvent.

The following abbreviations and symbols are used:

Δη optical anisotropy at 20 ° C and 589 nm,

Δε dielectric anisotropy at 20 ° C and 1 kHz,

Κρ., Τ (Ν, Ι) clearing point [° C].

All physical properties are and have been determined according to "Merck Liquid Crystals, Physical Properties of Liquid Crystals", Status Nov. 1997, Merck KGaA, Germany and are valid for a temperature of 20 ° C. The value of Δη is determined at 589 nm and the value of Δε is determined at 1 kHz, unless explicitly stated otherwise.

The following examples illustrate the present invention without it being intended to derive any limitation on the subject matter of the invention. applications

1) General procedure for the preparation of the devices according to the invention The liquid-crystalline medium (composition varies according to

below examples) is given in an electro-optical cell of a thickness of about 4 μιτι. The substrate material of the cells varies according to the examples below (ITO, glass or AL-3046 (90 ° grated

Polyimide, JSR Corporation)). The cells are equipped with 2 linear polarizers with parallel alignment of the polarization planes on the front and

Provided back of the cells. Finally, temperature-dependent measurements of the light transmission of the cells are carried out.

2) Examples of Liquid-Crystalline Media Used a) Mixture-1 + 0.3% N-2

b) Mixture-2 + 0.25% N-2

c) Mixture-3 + 0.25% N-2

d) Mixture-4 + 0.25% N-2

e) Mixture -5 + 1.0% N-8

f) Mixture -5 + 1.0% N-7

used components (N):

Liquid crystalline mixtures used:

3) Examples of devices according to the invention and their switching windows

The table below shows the results of combinations of media a) to f) with the different substrate materials AL-3046, ITO and glass in the devices according to the invention. For each device, the switching window, i. H. the area between the

Limit states A and B, given in degrees Celsius.

4) Switching operation of the devices according to the invention The devices according to the invention show in their entirety

Switching range ("switching window") a regular, gradual change of the transmission with the temperature.

By way of example, FIG. 1 shows the switching operation of a device comprising the medium a) and the substrate material ITO (1st row, 1st column of FIG

previous table) (triangle symbols). For comparison, the transmission change is shown for a device containing the medium a) but without component (N) (circular symbols). It can be seen that for the device according to the invention a gradual

Transition from high to low transmission with increasing temperature within a working range (switching window, indicated by line with arrowheads between the dashed lines) of about 40 - 70 ° C is present. In the device containing the liquid-crystalline medium without a component (N) there is no change in the transmission with the

Temperature.

Furthermore, in Fig. 2, the switching operation of a cell containing the

Medium c) and the substrate material AL-3046 shown (3rd row, 2nd column of the previous table). The obtained measured values for the transmission are entered as triangle symbols. For comparison, the

Transmission change for a device containing the medium c) but without component (N) shown (circle symbols).

It can be seen that for the device according to the invention there is a gradual transition from high to low transmission with increasing temperature within a working range (switching window, illustrated by a line with arrowheads between the dashed lines) of about 5-50 ° C. In the device containing the liquid-crystalline medium without a

Component (N) takes place virtually no change in the transmission with the temperature.

Claims

claims

Temperature-reactive device for regulating the transmission of light, characterized in that it contains a layer of a liquid-crystalline medium, wherein the liquid-crystalline medium

- One or more liquid crystalline compounds as well

- A component (N) containing nanoparticles and / or one or more compounds (V) having a three-dimensional structure and a molecular weight of more than 450 Da contains.

2. Apparatus according to claim 1, characterized in that the

Layer of the liquid-crystalline medium between two

Substrate layers is arranged.

3. Device according to claim 1 or 2, characterized in that it comprises two or more polarizers, one of which on one side of the layer of the liquid-crystalline medium and another on the opposite side of the layer of the liquid-crystalline

Medium is arranged.

4. Device according to one or more of claims 1 to 3, characterized in that the device contains no orientation layers adjacent to the layer of the liquid-crystalline medium.

5. Device according to one or more of claims 1 to 4, characterized in that the nanoparticles and / or the compound (V) carry at least one anchor group A ¹ , which is a non-covalent Interacts with surfaces of glass or metal and which represents an organic-chemical group.

6. Device according to one or more of claims 1 to 5, characterized in that the component (N) nanoparticles having a diameter of 1 nm to 50 nm.

7. Device according to one or more of claims 1 to 6, characterized in that the component (N) one or more

Compounds (V) with a three-dimensional structure and a

Molecular weight of more than 450 Da, which represent molecular cage compounds.

8. Device according to one or more of claims 1 to 7, characterized in that the component (N) one or more

Compounds (V) with a three-dimensional structure and a

9. Device according to one or more of claims 1 to 9, characterized in that it has a limit state A with a transmission T _A at a temperature less than a limit temperature ΘΑ and a limit state B with a transmission T _B at a temperature greater than a limit temperature Θ _Β , where:

10. Apparatus according to claim 9, characterized in that the

Limit temperature ΘΑ is between -15 and +25 ° C and that the

Limit temperature ΘΒ between 60 and 100 ° C is.

11. The device according to claim 9 or 10, characterized in that the transition between the two limit states A and B with increasing temperature and the transition between the two limit states B and A with decreasing temperature gradually over intermediate values of the transmission T runs.

12. Use of a device according to one or more of

Claims 1 to 11 for regulating the light entry and / or the energy input into an interior.

13. A method for producing a device according to one or more of claims 1 to 11, characterized in that a

liquid-crystalline medium containing

- One or more liquid crystalline compounds as well

- A component (N) containing nanoparticles and / or one or more compounds (V) having a three-dimensional structure and a molecular weight of at least 450 Da, is applied in a layer on a substrate layer.

14. Liquid-crystalline medium containing

- One or more liquid crystalline compounds as well

a component (N) containing nanoparticles and / or one or more compounds (V) having a three-dimensional structure and a molecular weight of more than 450 Da, characterized in that the liquid-crystalline medium has a dielectric anisotropy Δε, for which applies: -1.5 <Δε <1.5.

15. A method for temperature-dependent control of the light transmission by a device comprising a layer of a liquid-crystalline medium, characterized in that the liquid-crystalline medium

- One or more liquid crystalline compounds as well

- A component (N) containing nanoparticles and / or one or more compounds (V) having a three-dimensional structure and a molecular weight of at least 450 Da contains, and the liquid crystalline compounds change temperature dependent on a homeotropic orientation to a planar orientation.