Electromechanical converters using ferroelectric nematic materials.

Abstract

An electromechanical converter is provided that uses a ferroelectric nematic material. Improved electromechanical principles for converting electrical power into mechanical motion and vice versa are described using dielectrics with extreme relative permittivity. Non-magnetic devices are based on relative motion of dielectrics in the presence of an electric field. Energy-saving devices use high-performance dielectrics based on ferroelectric nematic liquid crystals. Linear and circular mechanical motions are proposed, including electromechanical actuators, non-magnetic motors and associated generators.

Description

[Technical field]

[0001] Improved electromechanical principles for converting electrical power into mechanical motion and vice versa are described using dielectric materials (dielectrics) with extreme relative permittivity. Non-magnetic devices are based on the relative motion of dielectrics in the presence of an electric field. The devices use high performance dielectrics based on ferroelectric nematic liquid crystals. Linear and circular mechanical motions are proposed, including electromechanical actuators, non-magnetic motors and associated generators. [Background technology]

[0002] Modern civilization relies heavily on the use of electricity to perform mechanical operations of all kinds, most of which are driven by electromagnetic motors in all kinds of machines, including but not limited to tools, pumps, vehicles, robotics, household appliances, toys, etc. Similarly, our electricity is generated by the action of generators, all of which are based on the same electromagnetic principles.

[0003] Modern electromagnetic motors and generators are very efficient due to the availability of powerful permanent magnets developed over the past few decades. However, electromagnetic principles have several inherent drawbacks, such as the complex manufacture of electric coils, the use of high currents at low speeds, the need for large amounts of copper and rare earth materials (e.g. neodymium) for the magnet materials, and heat generation. Miniaturization of magnetic motors is limited by the complexity of manufacturing magnetic coils and magnetic elements on a small scale.

[0004] Alternative electromechanical actions are known as electrostatic attraction and electrostatic repulsion. Electrostatic motors and generators have been proposed repeatedly. Usually the electrode gap is filled with air, vacuum or an insulator. Very high voltages are usually used for operation. At moderate voltages the mechanical output is much inferior to that of magnetic motors and so far there has been little commercial interest.

[0005] There is a high interest in improving alternative electromechanical converters. Most electromagnetic motors achieve optimum power efficiency only at a sufficient level of speed. Therefore, machines that require little power at low speeds or at standstill are desirable. The simple construction principle of the actuator or motor is very attractive, especially in terms of miniaturization and cost reduction. Non-magnetic power supply systems are also interesting from the point of view of working in environments sensitive to electromagnetic interference.

[0006] The dielectric constant of a material is well known for most materials. It can be determined by measuring the capacitance of a capacitor filled with the material compared to an empty capacitor. The dimensionless relative dielectric constant (ε r )teeth,

[0007]

number

[0008] The electric field acts on the dielectric material and vice versa. According to electrostatic theory, the energy density inside the capacitor is proportional to the dielectric constant (ε r ) depends linearly on the electric field E. If a dielectric only partially fills a capacitor under constant voltage, the dielectric is mechanically pulled into the electric field, maximizing the energy density in the capacitor. The force on the dielectric can be expressed as a pressure p on the surface of the dielectric that is in contact with the electric field E:

[0009]

number

[0010] Relative dielectric value ε in an electric field r 1 and ε r 2 For different dielectrics with

[0011]

number

[0012] In recent years, the field of application of liquid crystal compounds has expanded significantly to various types of display devices. Most of these devices, including all common LCD television sets, LCD desktop monitors and mobile LCD devices, employ an enantiotropic nematic liquid crystal phase. Several alternative liquid crystal phases are known, such as the ferroelectric smectic phase or blue phase. However, the ferroelectric nematic phase (N f The monotropic ferroelectric nematic liquid crystal phase (N-LC phase) has been hypothesized theoretically for decades, without the discovery of a suitable liquid crystal material with such nematic and ferroelectric properties. Recently, a few chemical structures have been reported that exhibit ferroelectric nematic behavior. For example, a ferroelectric nematic material of formula C was published in Atsutaka Manabe, Matthias Bremer, Martin Kraska (2021): Ferroelectric phase at and below room temperature, Liquid Crystals, Vol. 48, pp. 1079-1086 (DOI 10.1080 / 02678292.2021.1921867) (Non-Patent Document 1), which shows a monotropic ferroelectric nematic liquid crystal phase (N-LC phase) close to ambient temperature. f-LC phase).

[0013] [ka] [Prior art documents] [Patent documents]

[0014] [Patent Document 1] International Publication No. 2015 / 101405 [Non-patent literature]

[0015] [Non-Patent Document 1] Atsutaka Manabe, Matthias Bremer, Martin Kraska (2021): Ferroelectric phase at and below room temperature, Liquid Crystals, Volume 48, Pages 1079-1086 (DOI 10.1080 / 02678292.2021.1921867) DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0016] There remains a need to improve the temperature stability of the ferroelectric nematic phase at ambient temperatures and over long periods of time.

[0017] The use of fluorinated liquid crystal materials is known to those skilled in the art. Various compounds containing two 2,6-difluorinated 1,4-phenylene rings have already been described as liquid crystal or mesogenic materials, for example in WO 2015 / 101405 and elsewhere. The compounds proposed therein have been fully characterized, but have not been reported to have ferroelectric properties. [Means for solving the problem]

[0018] In a first aspect, the present invention provides an electromechanical transducer comprising two or more electrodes for generating an electric field in a spatial volume distributed between the at least two electrodes, and a dielectric material at least partially disposed within the spatial volume of said electric field between the at least two electrodes, However, the dielectric material is said to be capable of taking a spatially variable position relative to the electrodes, However, the dielectric material is preferably a ferroelectric nematic (N f ) phase, preferably an enantiotropic ferroelectric nematic phase, However, the ferroelectric nematic LC material relates to an electromechanical transducer comprising at least two compounds having the molecular structure of formula I:

[0019] [ka]

[0020] During the ceremony, A 1 teeth, [ka] represents A 2 teeth, [ka] represents A 3 teeth, [ka] or a single bond, R 1 represents an alkyl group having 1 to 12, preferably 1 to 8, more preferably 1 to 6, most preferably 1 to 5 C atoms (provided that in addition, one or more CH groups in these groups may be in each case independently of one another, -C≡C-, -CF2-O-, -OCF2-, -CH=CH ... [ka] or H, X is CN, F, CF3, -OCF3, -NCS, Cl, preferably CN or F; L 1 is H or CH3, Z 1 is CFO or -(CO)-O- or a single bond, Z 2 is CFO or -(CO)-O- or a single bond.

[0021] A further aspect of the present invention is a method of preparing an electromechanical transducer, comprising inserting a ferroelectric nematic liquid crystal medium as defined above and below into a defined spatial volume and attaching two or more electrodes, wherein the electrodes define a second spatial volume distributed between the at least two electrodes, and wherein a dielectric material is disposed in contact with or partially inside the second spatial volume.

[0022] In one aspect of the invention, an electromechanical transducer converts electrical impulses into mechanical motion. In another aspect, an electromechanical transducer converts mechanical motion into electrical impulses.

[0023] One aspect of the present invention relates to the use of liquid crystal media which exhibit a ferroelectric nematic liquid crystal phase over a substantial temperature range, preferably at ambient temperature. Preferably, these media comprise one or more compounds of formula I, more preferably each of formulae IA and IB, and one or more of IC-1 to IC-3 as defined below.

[0024] Ambient temperature, sometimes also called room temperature, means in the narrow sense herein a temperature of 20°C.

[0025] N for technical purposes fThe application of -LC phases has the obvious advantage of applicability to ambient temperatures: technical devices and electronic applications are usually designed to have a wide operating range above and below ambient temperature, respectively, e.g. 15°C to 25°C, preferably 0°C to 50°C, more preferably even higher.

[0026] The disclosure includes stable compounds suitable as component(s) of ferroelectric nematic liquid crystal media, particularly for application in the electromechanical devices of the present invention.

[0027] Surprisingly, liquid crystal media containing certain compounds selected as described below are capable of achieving a ferroelectric phase in a highly favorable temperature range, and the particular disclosed compounds in combination are N f It has been found that the compounds of the present invention are outstandingly very suitable as components of N-LCD media. They can be used to obtain liquid crystal media with unprecedented properties, including but not limited to those for electromechanical devices using the high dielectric constant of the material. The media and compounds used according to the present invention are sufficiently stable. In particular, they are distinguished by very high dielectric constants, in particular by very high dielectric anisotropy (Δε), and much lower threshold voltages are required to align them uniformly. The compounds have reasonably good solubility for compounds with comparable properties and are miscible with similar compounds. In addition, the compounds used according to the present invention have high clearing points. These compounds also have relatively low melting points or can be stably maintained below their melting point as supercooled melts. The present invention allows the desired N-LCD media to be obtained in a considerable operating range above and below room temperature. f -Allows for the formation of LC phases.

[0028] High dielectric constants allow for outstanding physical performance. High (relative) dielectric constants are particularly advantageous for dielectrics, since they provide a high relative permittivity in any given volume between the charged electrodes. This medium also has very low electrical conductivity, is an insulator, and because of their fluidity, it is not compatible with conventional high ε r It is more unique than materials (e.g. barium titanate). [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 shows a graph depicting the dielectric properties of Mixture Example 1 over the temperature range of −40 to 110° C. The T / εr graph, measured at 10 Hz and a voltage of about 50 mV, shows the value of the relative dielectric constant εr upon cooling. Between about 5 and 55° C., the value of εr has a maximum (plateau shape) and decreases towards higher temperatures. The maximum dielectric constant value of εr at about 52° C. is 42400.

[0030] [Diagram 2] Figure 2 shows an electromechanical actuator with two pairs of electrodes (1, 2) arranged along the path of a piston in a tube (6). The piston includes a housing (4) filled with a ferroelectric nematic LC dielectric material (3). A rod (5) is connected to the piston housing (4) to transmit the motion.

[0031] [Diagram 3] Figure 3 shows an electromechanical actuator comprising two pairs of electrodes (1, 2) arranged along the path of a piston (4) in a container (6), the piston (4) being made of a low εr dielectric material (dotted areas). The piston (4) is placed inside a container (6) which is filled with a ferroelectric nematic liquid crystal dielectric material (3) (hatched areas).

[0032] [Figure 4]Figures 4a and 4b show two views of a model of a rotary electric motor with a rotor containing a dielectric material and a stator containing electrodes. Figure 4a shows a cross-section of the motor with a rotor (1) holding a cavity (2) to be filled with dielectric material. The dielectric material can be filled through an opening that is sealed by a lid (3) (e.g. a screw) located away from the electrode. Next to the rotor and at a short distance from the side, a separate electrode (4) of similar size to the rotor is placed. The rotor is attached to a rotating central shaft (5), while the electrodes are stationary. Figure 4b shows an exploded view of the motor with the first and second sectors of the rotor (1, 2) and the electrode pairs (3, 4, 5, 6) that make up the stator. The distance between the rotor and the stator has been greatly enlarged (exploded view) for better visibility. The rotor is attached to a shaft (7) so that it can rotate. The first sector (1) of the rotor contains a ferroelectric nematic material with a high dielectric constant, and the second sector (2) contains other non-conductive insulating structural materials or voids, which materials typically have a low relative dielectric constant (εr<100). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] The driving force of the machine presented here is a higher dielectric constant ε r The actuation of a dielectric material into the space between the charged electrodes. During this actuation, the dielectric material is replaced by a lower εr material, either air or vacuum. That displacement can be used to induce mechanical motion or the motion of a fluid medium, which can be the liquid crystal itself, air or a hydraulic liquid.

[0034] Due to the significantly higher dielectric constant of the proposed ferroelectric nematic dielectrics, the mechanical forces or pressures obtained far exceed those obtainable by the prior art.

[0035] The movement of the dielectric is relative to the electrodes. In this sense, not only can the dielectric move in and out of the space between the electrodes, but the electrodes may move toward or away from the dielectric, or both. In a further preferred embodiment, only one electrode may move relative to one or more other electrode(s) and the dielectric.

[0036] Preferably, the converter according to the invention comprises mechanical means for inducing forces between the electrodes and the dielectric material. In a further preferred embodiment, the dielectric is enclosed in a container (housing, see container (4) in FIG. 2) for transmitting any forces to and from the dielectric. Preferably, the dielectric material or its housing is mechanically connected to a rod for transmitting forces or a shaft for transmitting torque and / or force (see rod (5) in FIG. 2).

[0037] In one aspect of the invention, the electromechanical transducer functions as a linear electromechanical actuator. In this embodiment, the movement of the machine is essentially linear, preferably back and forth. In a preferred embodiment, the machine comprises an enclosed space in which the LC material moves along a defined path by a driving electric field. This confined path may be a tube or a shaft, causing the dielectric to move. The medium may be a free-flowing bulk liquid or a dielectric confined in a container. The latter may be, illustratively and preferably, a hollow piston filled with the dielectric. In a preferred embodiment, the shape of the dielectric volume is adopted to the shape of the electrodes, which are normally flat. Thus, the dielectric material or its enclosing container may be in the shape of a rectangular parallelepiped, preferably with two opposite sides flat to allow for close proximity to the electrodes. Preferably, the distance between the electrodes and the corresponding thickness of the dielectric is in the range of 0.1 mm to 50 mm, preferably 5 mm or less. The output of the actuator does not depend directly on the distance between the electrodes, but rather on the strength of the electric field (~E 2) The achievable mechanical force is related to the area of ​​the dielectric boundary region moving in the spatial volume between the electrodes perpendicular to the direction of motion. However, increasing the electrode gap also leads to a decrease in the electric field at constant voltage on the electrodes, so increasing the volume by making the electrode gap thicker does not increase the force.

[0038] The present invention therefore also relates to an electromechanical transducer in which a liquid dielectric material is confined within a container.

[0039] Alternatively, the liquid dielectric material may be disposed within the machine as a bulk liquid with spatial confinement to allow flow of the material. The invention therefore also relates to an electromechanical transducer in which a dielectric material is disposed within a flow path within said spatial volume, and the spatially variable position of the dielectric material corresponds to a flow movement of the dielectric material within said flow path. As the material enters the space between the charged electrodes, flow is induced. The material pushes air or other solid or liquid material out of said space. This combined movement may be used mechanically in many conventional ways.

[0040] In a further preferred embodiment of the present invention, the electromechanical actuator comprises f A solid non-ferroelectric dielectric material (preferably ε r <100). Preferably, the volume containing both materials is inside a container, preferably a sealed container. Both materials are present between two or more electrodes. In this embodiment, the lower ε r The non-ferroelectric dielectric material is pushed out of the electric field, while the N f The transducer operates in the reverse mode, where the -LC dielectric material is placed in an electric field. Figure 3 shows an example of an electromechanical transducer adapted for linear motion. Liquid N on either side of the piston (4) f The reservoir of -LC dielectric may be in communication via a bypass tube or via one or more through holes in the piston so that the medium is in equilibrium between the partial volumes. In a further preferred embodiment, the pressure and flow rate in the volume of liquid medium is used for the hydraulic system (hydraulic actuator). In this embodiment, the low ε rThe material preferably fits snugly against the container wall as it acts as a piston on the liquid medium.

[0041] In another aspect of the invention, the electromechanical transducer operates as a circular electric machine, which is also treated as an (electric) motor. In this embodiment, the principle of a linear actuator, including linear motion as described above, is modified to rotary motion. The motor has a rotor and a stator, similar to a conventional magnetic motor. It preferably has at least three pairs of electrodes and at least two separate dielectric volumes. To complete the circular rotation as the motor does, the electric field must be a time-modulated field that is adapted to the rotation mode. Such a time modulation of the magnetic field, adapted to the repetitive twisting of the rotor, is known from the drive of conventional electromagnetic motors, where the magnetic field is modulated by controlling the power supply. In the present case, the voltage on the electrodes is applied by the power supply as the dielectric enters the volume of the electric field. At this stage, a physical force is generated. No voltage is applied when the dielectric moves. The potential of the electrodes at this stage may be set to zero. Optionally, the charge present between a pair of electrodes is reused by redirecting it or (partially) directing it to the other pair of electrodes. The modulation of the electric field may be by a conventional commutator (e.g. using brushes on sector-shaped twisted electrodes) or by applying a respective amplified electronic signal (brushless drive). Several circuits and controllers for electric motors with passive rotors (eg, stepper motors, brushless motors, etc.) are known to those skilled in the art.

[0042] The motor may be driven, for example, by a pulsed DC voltage or a polyphase (eg, three-phase) DC voltage or an AC voltage, each phase corresponding to a pair of electrodes.

[0043] The dielectric and electrodes advantageously have rounded shapes to avoid excessive electric fields at corners and edges.

[0044] Generator The principle is reversible with respect to electricity generation when an initial potential is applied to a pair of electrodes as a dielectric moves in and out of the volume between the electrodes. The electrical signal generated is superimposed on the initial voltage. The change in voltage may be converted by conventional means to another DC voltage or current. In similar setups as actuators and motors in this mode, mechanical motion is converted to a change in voltage on the electrodes and may be used as a power source. The power output is related to the frequency of the movement or rotation, if applicable.

[0045] The advantages of the electromechanical converter of the present invention may be viewed from various perspectives, either in comparison with electromagnetic devices or in comparison with electrostatic machines.

[0046] Compared to electromagnetic motors and generators, the structure of the converter of the present invention is relatively simple, since there is no need to form a coil. The electrical part is replaced by a pair of electrodes. This makes it easier to miniaturize than coil-based devices. Therefore, a preferred embodiment of the present invention relates to an electromechanical transduction system having a dimension of 1 mm or less, more preferably 100 μm or less. This dimension is defined as the distance of two electrodes across a spatial volume containing a dielectric material. In another preferred embodiment, the electromechanical transduction system is integrated with electronic structures on a semiconductor chip, or is a microelectromechanical system, also known as MEMS (micro electromechanical system), including but not limited to MEMS sensors.

[0047] It is noted that due to the different characteristics of the converter in terms of power efficiency, very low currents are generated during start-up or during stop of operation. In electromagnetic motors, slow movement generates excessive currents, which leads to power loss and heat generation in the coils. A further problem in conventional motors is the loss due to electromagnetic induction in all magnetizable parts, e.g. coil cores, magnets, etc. Such is not known for electrostatic rotors made from non-ferrite based isolators. Furthermore, the present invention does not employ rare earth materials for magnets (e.g. neodymium magnets) but is based on abundantly available organic chemicals and normal metallic conductors.

[0048] In another aspect of the invention, the setting of the electromechanical converter is changed in that the dielectric is stationary as the electrode(s) move (linearly or rotationally) relative to the dielectric. Herein, a mechanical commutator and a moving electrode may be integrated into the moving part in combination.

[0049] In another aspect of the invention, the electromechanical converter is modified in that parallel machines are combined into one system to perform more power conversion. This may be done by stacking multiple units of alternating dielectric material (pistons or rotors) and electrodes. Alternatively, parallel units may be introduced by placing more sectors of dielectric and / or electrodes in the device according to Figures 4a / 4b.

[0050] The liquid crystal medium for use in the device comprising at least two compounds of formula I is stable in the ferroelectric nematic phase at ambient temperature. It operates from very low voltages, such as 2 V, up to very high voltages, up to the breakdown voltage (arc / short circuit) required for various levels of power. Prior art materials (e.g. barium titanate) have a relative dielectric constant ε 0.01, which is required for performance. r To achieve high values ​​of θ, a much higher initial electric field is required.

[0051] The driving schemes of capacitor type motors are known to those skilled in the art from earlier theoretical studies and are somewhat similar to the driving of some electromagnetic motors. The motor according to FIG. 4 is driven with three-phase periodically alternating potentials at the three electrodes. This can be a suitably connected commutator or an external electric system. Similar driving schemes are known from conventional brushless motors and stepper motors with several stator coils. The driving direction is determined by the initial rotation caused in the first part (sector) of the dielectric entering the first electric field between the electrodes, or simply by an external stimulus.

[0052] In the following, dielectric media including ferroelectric nematic liquid crystal media are further described.

[0053] Ferroelectric nematics (N f The liquid crystal (LC) material in the 1H-phase preferably comprises at least 20% by weight or more, preferably 50% by weight or more, more preferably 60% by weight or more, even more preferably 65% ​​by weight or more of compounds selected from compounds having a molecular structure of formula I. The material or medium preferably comprises three, four, five or six or more compounds of formula I. Preferably, the compounds of formula I are selected from the compounds of formulas IA and IB below, preferably in the percentages given for each formula independently for each formula.

[0054] In a more preferred embodiment, the invention uses a liquid-crystalline medium comprising at least 10% by weight, preferably at least 15% by weight, of one or more compounds of formula IA, at least 10% by weight, preferably at least 15% by weight, of one or more compounds of formula IB and at least 10% by weight, preferably at least 15% by weight, more preferably at least 20% by weight of one or more compounds selected from the formulae IC-1 to IC-3.

[0055] [ka]

[0056] [ka]

[0057] [ka]

[0058] During the ceremony X 1B represents -CN or -NCS, preferably -CN, X 1C represents -CN, F, CF3, -OCF3, -NCS, SF5 or O-CF=CF2, preferably -CN or F, most preferably CN, Z 1A and Z1B represent, independently of one another, -(CO)-O- or -CF2-O- or a single bond, preferably -(CO)-O- or -CF2-O-, Z 2A and Z 2B represent, independently of one another, a single bond, -(CO)-O- or -CF2-O-, preferably a single bond, Z 1C and Z 2C One of the two groups represents -(CO)-O- or -CF2-O-, and the other represents a single bond. 1C is -(CO)-O- or -CF2-O-, and Z 2C is a single bond, L 1A , L 1B and L 1C each independently represents H or CH3, preferably H, L 2A is F or H, preferably F; L 2C is F or H, preferably F; [ka] represents [ka] represents In the formula, L 8B represents alkyl, alkoxy or alkoxyalkyl having 1 to 7 C atoms, preferably CH3, OCH3, OCH2CH3, CH2OCH3, CH2OCH2CH3, CH2CH2OCH3, CH2CH2OCH2CH3 or CH2CH2CH2OCH3, [ka] represents [ka] represents m, n are 0, 1 or 2, with the proviso that (m+n) is 1; R 1A , R1B and R 1C each independently represent an alkyl group having 1 to 12, preferably 1 to 8, more preferably 1 to 6, most preferably 1 to 5 C atoms (provided that in addition, one or more CH groups in these groups may in each case independently be -C≡C-, -CF2-O-, -OCF2-, -CH=CH ... [ka] -O-, -S-, -(CO)-O- or -O-(CO)-, provided that in addition one or more H atoms may be replaced by halogen; Preferably R 1A , R 1B and R 1C are independently halogenated or unsubstituted alkyl groups having 1 to 10 C atoms, provided that in addition, one or more CH groups in these groups may be replaced by -O- or -CH=CH- in such a way that no O atom is directly linked.

[0059] Percentages are provided in the context that the entire medium constitutes 100% by weight of the medium.

[0060] The group R in the formulae IA, IB and IC-1 to IC-3 and in each of their sub-formulae 1A , R 1B and R 1C preferably represents an alkyl having 1 to 8 carbon atoms, an alkoxy having 1 to 8 carbon atoms or an alkenyl having 2 to 8 carbon atoms. These alkyl chains are preferably linear or they are preferably 1C In the case of R, it is preferably branched with a single methyl or ethyl substituent at the 2- or 3-position. 1A , R 1B and R 1Cparticularly preferably denotes a linear alkyl group having 1 to 7 C atoms or an unbranched alkenyl group having 2 to 8 C atoms, in particular an unbranched alkyl group having 1 to 5 C atoms.

[0061] Alternatively preferred groups R 1A , R 1B and R 1C is selected from cyclopentyl, 2-fluoroethyl, cyclopropylmethyl, cyclopentylmethyl, cyclopentylmethoxy, cyclobutylmethyl, 2-methylcyclopropyl, 2-methylcyclobutyl, 2-methylbutyl, 2-ethylpentyl, and 2-alkyloxyethoxy.

[0062] Branched or substituted end groups R 1A , R 1B and R 1C Compounds of formulae IA, IB and IC1 to IC-3, each containing the group R 1A , R 1B and R 1C is preferably linear.

[0063] base R 1A , R 1B and R 1C are each particularly preferably selected from the lower substructures.

[0064] [ka]

[0065] However, the following abbreviations are used for the end groups:

[0066] [ka]

[0067] In a preferred embodiment, the medium according to the invention preferably comprises one, two or more compounds of formula IA-1, preferably selected from the group of formulae IA-1 to IA-3, preferably of formula IA-1.

[0068] [ka]

[0069] [ka]

[0070] where the parameters have the respective meanings given above, preferably Z 1A represents -CF2-O-.

[0071] In a preferred embodiment, the medium according to the invention preferably comprises one, two or more compounds of the formula IB-1 and / or IB-2, preferably of the formula IB-1, preferably selected from the group of the following formulae IB-1-1 to IB-2-3:

[0072] [ka]

[0073] R 1B represents an alkyl group having 1 to 12, preferably 1 to 7, more preferably 1 to 6, most preferably 1 to 5 C atoms (provided that in addition, one or more CH groups in these groups may be independently selected from -C≡C-, -CF2-O-, -OCF2-, -CH=CH ... [ka] or H, Preferably R1B is a halogenated or unsubstituted alkyl radical having 1 to 12 C atoms, with the proviso that in addition, one or more CH groups in these radicals may in each case independently be replaced by -C≡C- or -CH=CH-, [ka] represents, and Z 1B , Z 2B independently represent -(CO)-O- or -CF2-O-.

[0074] [ka]

[0075] where the parameters have the respective meanings given above. And in particular in the formulae IB-1-1 to IB-1-3, Z 1B preferably represents -CF2-O-, and in particular in the formulae IB-2-1 and IB-2-2, Z 2B preferably represents -CF2-O-, and in particular in formula IB-2-3, Z 2B preferably represents -C(O)O-.

[0076] In a preferred embodiment, the medium according to the invention preferably comprises one, two or more compounds selected from the group of formulae IC-1-1-1 to IC-3-5-2, preferably selected from the group of formulae IC-1-1-1, IC-1-1-2, IC-1-1-3, IC-1-1-4, IC-3-1-1 and IC-3-2-1.

[0077] [ka]

[0078] In the formula, A 1C and A 2C is defined as above.

[0079] [ka]

[0080] [ka]

[0081] [ka]

[0082] where the parameters have the respective meanings given above, preferably L 1C represents H, Z 1C represents -CF2-O- or -(CO)-O-, and X 1C represents -CN or F, preferably -CN.

[0083] Particularly preferred compounds of the formulae IC-1-1 to IC-1-4 for use in the medium are the compounds of the following formulae:

[0084] [ka]

[0085] where the parameters are defined as above, and preferably L 1C is H.

[0086] In a preferred embodiment of the invention the medium comprises up to 100% of one or more compounds, preferably 3, 4, 5 or 6 or more compounds selected from group 1 of compounds, group of compounds of formulae IA, IB and IC-1 / -2 / -3. In this embodiment the medium preferably consists mainly of these compounds, more preferably it consists essentially of them and most preferably it consists substantially completely of them.

[0087] For the purposes of this invention, unless otherwise indicated in particular cases, the following definitions apply with respect to the identification of the components of the compositions.

[0088] "Comprises": The concentration of the component of interest in the composition is preferably 5% or more, particularly preferably 10% or more, very particularly preferably 20% or more.

[0089] "Consists mainly of": The concentration of the component of interest in the composition is preferably 50% or more, particularly preferably 55% or more, very particularly preferably 60% or more.

[0090] "Consists essentially of": The concentration of the component of interest in the composition is preferably 80% or more, particularly preferably 90% or more, very particularly preferably 95% or more.

[0091] "Consists essentially completely of": The concentration of the component of interest in the composition is preferably 98% or more, particularly preferably 99% or more, very particularly preferably 100.0%.

[0092] Preferably, the media according to the present application meet one or more of the following conditions:

[0093] 20% by weight or more of compounds of formula IA, more preferably 25% by weight or more, more preferably 27% by weight or more, most preferably 32% by weight or more of compounds of formula IA,

[0094] at least 17% by weight of compounds of formula IB, more preferably at least 20% by weight, more preferably at least 22% by weight, most preferably at least 25% by weight of compounds of formula IB,

[0095] 20% by weight or more, preferably 25% by weight or more, of compounds selected from the formulae IC-1, IC-2 and IC-3, more preferably 28% by weight or more, more preferably 32% by weight or more, most preferably 34% by weight or more,

[0096] optionally 2% by weight or more of compounds of formula ID (ID-1, ID-2, ID-3, ID-4), more preferably 5% by weight or more, more preferably 10% by weight or more, most preferably 15% by weight or more of compounds of formula ID,

[0097] one, two or more, preferably three or more, compounds of formula IA-1-1, preferably of formula DUUQU-nF, most preferably selected from the group of compounds DUUQU-2-F, DUUQU-3-F, DUUQU-4-F and DUUQU-5-F and DUUQU-6-F,

[0098] one, two or more, preferably three or more, compounds of formula IB-1, preferably of formula GUUQU-nN and / or DUUQU-nN, most preferably selected from the group of compounds GUUQU-2-N, GUUQU-3-N, GUUQU-4-N, GUUQU-5-N, GUUQU-6-N, GUUQU-7-N, DUUQU-2-N, DUUQU-3-N, DUUQU-4-N, DUUQU-5-N and DUUQU-6-N,

[0099] one, two or more compounds of formula IA-1-3, preferably of formula GUUQU-nF, more preferably selected from the group of compounds GUUQU-3-F, GUUQU-4-F and GUUQU-5-F,

[0100] one, two or more compounds of formula IB-1-3, preferably of formula DUUQU-nN, more preferably selected from the group of compounds DUUQU-3-N, DUUQU-4-N and DUUQU-5-N,

[0101] one, two or more compounds of formula IC-1-1, preferably of formula MUZU-nN or MUQU-nN, more preferably selected from the group of compounds MUZU-2-N, MUZU-3-N, MUZU-4-N and MUZU-5-N,

[0102] one, two or more compounds of formula IC-3, preferably selected from the formula MUU-nN or UMU-nN, more preferably selected from the group of compounds MUU-3-N, MUU-4-N, MUU-5-F, UMU-3-N, UMU-4-N and UMU-5-N,

[0103] one, two or more compounds of formula IC-1-1, preferably selected from the formula GUZU-nN or GUQU-nN, more preferably selected from the group of compounds GUZU-3-N, GUZU-4-N, GUZU-5-F, GUQU-3-N, GUQU-4-N and GUQU-5-N,

[0104] and / or one, two or more compounds selected from the group of formulae IC-1-1-3 and IC-1-1-4, preferably from the group of formulae UUZU-nN and / or UUQU-nN, most preferably from the group of compounds UUZU-2-N, UUZU-3-N, UUZU-4-N, UUZU-5-N, UUQU-2-N, UUQU-3-N and UUQU-4-N,

[0105] In the formula, n is 1, 2, 3, 4, 5, 6 or 7.

[0106] In another preferred embodiment of the present invention, said compounds of formulae IA, IB and IC-1 / -2 / -3 are a first group of compounds, compound group 1. In this embodiment, the concentration of the compounds of compound group 1 is preferably 70% or more, preferably 80% or more, more preferably in the range of 90% or more to 100% or less.

[0107] In addition to the compounds of the formulae IA, IB and IC-1 / -2 / -3, the medium according to the invention optionally, preferably essentially, comprises one, two or more compounds selected from the formulae ID-1 to ID-4.

[0108] [ka]

[0109] X D represents CN, F, CF3, -OCF3, NCS, SF5 or O-CF=CF2, preferably -CN, F, -CF3, -OCF3, -Cl or -NCS, most preferably F or CN, L 1D , L 2D , L 3D , L 4D , L 5D , L 6D and L 7D independently represent F, H, alkyl, alkoxy or alkoxyalkyl, each having 1 to 7 C atoms, preferably H, F, CH3, OCH3, OCH2CH3, CH2OCH3, CH2OCH2CH3, CH2CH2OCH3, CH2CH2OCH2CH3 or CH2CH2CH2OCH3, Z 1D and Z 2D represent, independently of each other, -(CO)-O-, -CF2-O-, a single bond, and preferably both -(CO)-O-, R 1Drepresents an alkyl group having 1 to 12 C atoms, preferably 1 to 7, more preferably 1 to 6, most preferably 1 to 5 C atoms (provided that in addition, one or more CH groups in these groups may be -C≡C-, -CF2-O-, -OCF2-, -CH=CH-, ... [ka] -O-, -S-, -(CO)-O- or -O-(CO)-, provided that in addition one or more H atoms may be replaced by halogen; Preferably R 1D is a halogenated or unsubstituted alkyl radical having 1 to 12 C atoms, with the proviso that in addition, one or more CH groups in these radicals may in each case independently be replaced by -C≡C- or -CH=CH-, R 2D represents alkyl, alkoxy or alkoxyalkyl, each having 1 to 7 C atoms, preferably CH3, OCH3, OCH2CH3, CH2OCH3, CH2OCH2CH3, CH2CH2OCH3, CH2CH2OCH2CH3 or CH2CH2CH2OCH3, [ka] represents L 8D represents alkyl, alkoxy or alkoxyalkyl, each having 1 to 7 C atoms, preferably CH3, OCH3, OCH2CH3, CH2OCH3, CH2OCH2CH3, CH2CH2OCH3, CH2CH2OCH2CH3 or CH2CH2CH2OCH3.

[0110] Preferably, it comprises one or more of formulae ID-1-1 to ID-3-1.

[0111] [ka]

[0112] In the formula, the variable group R 1D and L 8D is defined as above.

[0113] The corresponding starting materials can generally be readily prepared by those skilled in the art by synthetic methods known from the literature or are commercially available. The reaction methods and reagents used are in principle known from the literature.

[0114] In the present disclosure, the 2,5-disubstituted dioxane ring of the formula: [ka] Preferably, the dioxane ring is in the 2,5-trans configuration, i.e., the substituents R are both equatorial in the preferred chair conformation. [ka] Likewise preferably it represents a tetrahydropyran ring in the 2,5-trans configuration, ie the substituents are both equatorial in the preferably preferred chair conformation.

[0115] The liquid crystal medium used according to the invention has a wide temperature range of the ferroelectric nematic phase. It exhibits a range of the ferroelectric nematic phase at 20° and above (ambient temperature). It spans the range of most technical interest at least from 10 to 50° C. and significantly beyond lower and / or higher temperatures. It is therefore suitable for all kinds of domestic or industrial use and even outdoors with some restrictions. The medium exhibits a ferroelectric nematic phase in a temperature range at least extending over 20 Kelvin, more preferably extending over 30 K, most preferably extending over 40 K. Preferably the ferroelectric phase is obtained independently of the previous temperature and phase (enantiotropic ferroelectric nematic phase). The achievable combinations of temperature range, clearing point, low-temperature stability (LTS), (specific) dielectric constant, dielectric anisotropy and optical anisotropy of the ferroelectric nematic phase comprising the compounds of formulae IA, IB and IC-1 / -2 / -3 are far superior to previous materials of that kind from the prior art. Previously, only a limited selection of single compound materials having a limited ferroelectric nematic phase range were available.

[0116] The liquid crystal media used according to the invention preferably exhibit a temperature range of the ferroelectric nematic phase which is at least 20 degrees wide, which preferably extends over a range of at least 40 degrees, more preferably at least 60 degrees.

[0117] Preferably, the liquid crystal medium used according to the present invention exhibits a ferroelectric nematic phase at temperatures of 10°C to 30°C, more preferably 10°C to 40°C, more preferably 10°C to 50°C, more preferably 0°C to 50°C, and most preferably -10°C to 50°C.

[0118] In another preferred embodiment, the liquid crystal medium used according to the present invention exhibits a ferroelectric nematic phase preferably at 10°C to 40°C, more preferably at 10°C to 50°C, more preferably at 10°C to 60°C, and most preferably at 10°C to 70°C.

[0119] The liquid crystal media used according to the invention exhibit outstanding dielectric properties. Their excellent properties, such as their very high dielectric constant ε and their insulating properties, enable the media to function in electromechanical devices, including generators (i.e. energy harvesting devices) and actuators.

[0120] Preferably, the medium according to the invention has an ε of 15000 or more, even more preferably 30000 or more, more preferably 35000 or more. r values ​​(at 20° C. and 10 Hz).

[0121] These advantageous dielectric properties are primarily achieved at temperatures where the medium is in the ferroelectric nematic phase. The dielectric properties may exhibit hysteretic behavior, especially with respect to changes in temperature, in which case the value obtained at a certain temperature may depend on the history of the material, i.e., whether it is being heated or cooled.

[0122] The liquid-crystalline media according to the invention preferably contain from 2 to 40, particularly preferably from 4 to 20, compounds as further components in addition to one or more compounds according to the invention. In particular, these media may contain from 1 to 25 components in addition to one or more compounds according to the invention. These further components are preferably selected from ferroelectric nematic or nematogenic (monotropic or isotropic) substances.

[0123] Prior art ferroelectric materials and similar compounds with high dielectric constants for combination with the present material are selected, for example, from the following structures:

[0124] [ka]

[0125] The medium used according to the invention preferably comprises from 1% to 100%, more preferably from 10% to 100%, particularly preferably from 50% to 100%, of the compounds of the formulae IA and / or IB and / or IC-1 / IC-2 / IC-3 which are preferably used according to the invention.

[0126] The expression "alkyl" embraces unbranched and branched alkyl radicals having 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, particularly preferably the unbranched radicals methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl and n-heptyl, furthermore the radicals n-butyl, n-pentyl, n-hexyl and n-heptyl, which are alternatively substituted by one methyl, ethyl or propyl. Radicals having 1 to 5 carbon atoms are generally preferred.

[0127] The term "alkenyl" embraces unbranched and branched alkenyl groups having up to 12 carbon atoms, in particular unbranched groups. Particularly preferred alkenyl groups are C2-C7-1E-alkenyl, C4-C7-3E-alkenyl, C5-C7-4-alkenyl, C6-C7-5-alkenyl and C7-6-alkenyl, in particular C2-C7-1E-alkenyl, C4-C7-3E-alkenyl and C5-C7-4-alkenyl. Examples of preferred alkenyl groups are vinyl, 1E-propenyl, 1E-butenyl, 1E-pentenyl, 1E-hexenyl, 1E-heptenyl, 3-butenyl, 3E-pentenyl, 3E-hexenyl, 3E-heptenyl, 4-pentenyl, 4Z-hexenyl, 4E-hexenyl, 4Z-heptenyl, 5-hexenyl, 6-heptenyl, etc. Groups having 2 to 5 carbon atoms are generally preferred.

[0128] The expression "halogenated alkyl group" preferably includes mono- or polyfluorinated and / or chlorinated groups. Perhalogenated groups are included. Fluorinated alkyl groups are particularly preferred, in particular CF3, CH2CF3, CH2CHF2, CHF2, CH2F, CHFCF3 and CF2CHFCF3. The expression "halogenated alkenyl group" and related expressions are explained accordingly.

[0129] The following examples are intended to illustrate the present invention without being intended to limit it, and those skilled in the art will be able to obtain from the examples details not specifically given in the general description, and will be able to generalize them according to their general expertise and apply them to their specific problems.

[0130] Above and below, percentage data are expressed as % by weight. Unless otherwise stated, for example, melting point T(C,N), smectic (Sm) to nematic (N) phase transition T(S,N) and clearing point T(N,I), respectively T(N f All temperature values ​​given in this application, such as ,I) are given in degrees Celsius (°C) and all temperature differences are correspondingly given in degrees difference (° or degrees). Furthermore, C is the liquid crystal state, N is the nematic phase, Nf is the ferroelectric nematic phase, Sm is the smectic phase (more specifically SmA, SmB, etc.), Tg is the glass transition temperature and I is the isotropic phase. The data between these symbols represent the transition temperatures. Δn represents the optical anisotropy (589 nm, 20°C) and Δε represents the dielectric anisotropy (1 kHz, 20°C).

[0131] The physical, physicochemical and electro-optical parameters are determined in accordance with generally known methods, as described, inter alia, in the document "Merck Liquid Crystals - Licristal® - Physical Properties of Liquid Crystals - Description of Measurement Methods", 1998, Merck AG, Darmstadt.

[0132] The appearance of the ferroelectric nematic phase of the material is identified using differential scanning calorimetry (DSC) and by observing the texture under a polarized light microscope with a hot stage for controlled cooling or heating, respectively, as well as the temperature dependence of the dielectric properties. The transition temperature is primarily determined by detecting the optical behavior under a polarized light microscope.

[0133] The dielectric anisotropy Δε of the individual substances is determined at 20 ° C and 1 kHz. For this purpose, 5-10% by weight of the substances to be considered and measured are dissolved in the dielectrically positive mixture ZLI-4792 (Merck) and the measured values ​​are extrapolated to a concentration of 100%. The optical anisotropy Δn is determined at 20 ° C and a wavelength of 589.3 nm.

[0134] The dielectric constant (ε r ) is determined directly by measuring the capacitance of at least one test cell containing the compound, with homeotropic and homogeneous orientation, respectively, and with a cell thickness of 250 μm. The temperature is controlled by a Novocontrol Novocool system set to apply a temperature gradient of + / -1 K / min; + / -2 K / min; + / -5 K / min; + / -10 K / min to the sample cell. The capacitance is measured with a Novocontrol α-N analyzer at a frequency of 1 kHz or 10 Hz, with a standard voltage lowered from 50 mV to 0.1 mV below the threshold of the measured compound. Measurements are performed both during heating and cooling of the sample (one or more).

[0135] In this application, unless expressly indicated otherwise, the plural of the terms refers to both the singular and the plural, and vice versa. Further combinations of the embodiments and variations of the invention according to the detailed description arise from the appended claims or from multiple combinations of these claims. EXAMPLES

[0136] The invention will now be described in more detail by the following non-limiting examples.

[0137] Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The preceding preferred specific embodiments are therefore to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.

[0138] From the foregoing description, those skilled in the art can easily ascertain the essential features of the present invention, and can make various modifications and changes to adapt the present invention to various usages and conditions without departing from the spirit and scope thereof.

[0139] This applies both to the medium as a composition with components which may be groups of compounds and individual compounds of the composition, and also to groups of compounds with their respective components and compounds. As far as the concentration of the individual compounds in relation to the medium as a whole is concerned, the term "comprising" means that the concentration of the compound(s) or compounds(s) in question is preferably 1% or more, particularly preferably 2% or more, very particularly preferably 4% or more.

[0140] In the present invention, [ka] represents trans-1,4-cyclohexylene, [ka] represents a mixture of both cis- and trans-1,4-cyclohexylene, [ka] represents 1,4-phenylene.

[0141] In the present invention, the expression "dielectrically positive compound" means a compound with Δε>1.5, the expression "dielectrically neutral compound" means a compound with -1.5≦Δε≦1.5, and the expression "dielectrically negative compound" means a compound with Δε<-1.5. The dielectric anisotropy of a compound is determined here by dissolving 10% of the compound in a liquid crystal host and determining the capacitance of the resulting mixture at 1 kHz in at least one test cell with a cell thickness of 20 μm and in each case homeotropic and homogeneous surface alignment. The measuring voltage is typically between 0.5 V and 1.0 V, but always below the capacitance threshold of the respective liquid crystal mixture (material) under consideration.

[0142] The liquid crystal medium according to the invention may also contain further additives, such as, for example, stabilizers, in the usual amounts, if necessary. The amount of these additives used is preferably in total 0% to 10%, particularly preferably 0.1% to 6%, based on the amount of the entire mixture. The concentration of each compound used is preferably 0.1% to 3%. The concentrations of these and similar additives are generally not taken into account when specifying the concentration and concentration range of the liquid crystal compounds in the liquid crystal medium.

[0143] For the purposes of the present invention, all concentrations are given in percentages by weight, unless expressly stated otherwise, and relate to the corresponding mixture as a whole or to the mixture components as a whole, unless expressly stated otherwise. In this context, the term "mixture" describes a liquid-crystalline medium.

[0144] Unless otherwise stated, the following symbols are used: T(N,I) f ,I) (or clp.) Clearing point (℃).

[0145] Dielectric properties at 1 kHz and preferably at 20°C or each specified temperature: Δε for dielectric anisotropy and specifically for selection data of single compounds.

[0146] and specifically for data from screening of the respective compounds in the nematic host mixture ZLI-4792: n e The extraordinary refractive index measured at 20°C and 589 nm, n0Normal refractive index measured at 20°C and 589 nm, and Δn Optical anisotropy measured at 20° C. and 589 nm.

[0147] The following examples are intended to illustrate the present invention without limiting it. However, the following examples provide the skilled artisan with the preferred mixing concepts, together with the preferred compounds, their respective concentrations and their combinations with each other. In addition, the following examples illustrate the feasible properties and property combinations.

[0148] Definitions of structural elements by abbreviations for use in acronyms for chemical compounds.

[0149] <Table A: Ring elements>

[0150] [Table 1]

[0151] [Table 2]

[0152] <Table B: Cross-linking units>

[0153] [Table 3]

[0154] <Table C: Terminal group>

[0155] [Table 4]

[0156] where n and m each represent an integer and the three dots "..." are spaces for other abbreviations from the table.

[0157] In addition to the compounds of the formulae IA, IB and IC-1 / -2 / -3 the mixtures according to the invention preferably comprise one or more of the compounds mentioned below.

[0158] The following abbreviations are used: (n, m, k and l are each independently an integer, preferably 1 to 9, preferably 1 to 7, and k and l may be 0, preferably 0 to 4, more preferably 0 or 2, and most preferably 2; n is preferably 1, 2, 3, 4 or 5; in the combination "-nO-", it is preferably 1, 2, 3 or 4, more preferably 2 or 4; m is preferably 1, 2, 3, 4 or 5; in the combination "-Om", it is preferably 1, 2, 3 or 4, more preferably 2 or 4. The combination "-lVm" is preferably "2V1".)

[0159] In the present invention and the following examples, the structures of the liquid crystal compounds are represented by their initial letters, and the conversion to chemical formulas is performed according to Tables A to C above. n H 2n+1 , C m H 2m+1 and C l H 2l+1 or C n H 2n , C m H 2m and C l H 2l are linear alkyl or alkenyl groups having n, m and l C atoms, respectively. Preferably, n, m and l are each, independently of one another, 1, 2, 3, 4, 5, 6 or 7. Table A shows the codes for the ring elements of the core structure of the compounds, Table B lists the bridging groups, and Table C lists the meaning of the codes for the left and right terminal groups of the molecule. The initial letter consists of the code for the ring element with any linking groups present, followed by a first hyphen and the code for the left terminal group, and a second hyphen and the code for the right terminal group. Table D shows exemplary structures of the compounds with their respective abbreviations.

[0160] Examples of preferred compounds of formula IA

[0161] [Table 5]

[0162] Examples of preferred compounds of formula IB

[0163] [Table 6]

[0164] Examples of preferred compounds of formula IC-1

[0165] [Table 7]

[0166] Examples of preferred compounds of formula IC-3

[0167] [Table 8]

[0168] Optionally Used Further Compounds

[0169] [Table 9]

[0170] [Table 10]

[0171] In the formula, n is 0, 1, 2, 3, 4, 5, 6, 7, etc., preferably 0, 1, 2, 3, 4 or 5.

[0172] <Mixture example> The following exemplary mixtures are disclosed. The preparation of the compounds is carried out in the same manner as that of the same or similar structure in the previous publications. The preparation of the mixtures is carried out in the conventional manner by combining the necessary materials and homogenizing them at an appropriate high temperature.

[0173] <Mixture example 1> The following mixture (M-1) is prepared:

[0174] [Table 11]

[0175] <Mixture example 2> The following mixture (M-2) is prepared:

[0176] [Table 12]

[0177] <Mixture example 3> The following mixture (M-3) is prepared:

[0178] [Table 13]

[0179] These are the relative dielectric constants ε r It is the highest value among all.

[0180] <Mixture example 4> The following mixture (M-4) is prepared:

[0181] [Table 14]

[0182] <Mixture example 5> The following mixture (M-5) is prepared:

[0183] [Table 15]

[0184] <Mixture example 6> The following mixture (M-6) is prepared:

[0185] [Table 16]

[0186] <Mixture example 7> The following mixture (M-7) is prepared:

[0187] [Table 17]

[0188] <Mixture example 8> The following mixture (M-8) is prepared:

[0189] [Table 18]

[0190] <Mixture example 9> The following mixture (M-9) is prepared:

[0191] [Table 19]

[0192] <Mixture example 10> The following mixture (M-10) is prepared:

[0193] [Table 20] c ) Value when cooled

[0194] <Mixture example 11> The following mixture (M-11) is prepared:

[0195] [Table 21] c ) Value when cooled

[0196] <Mixture example 12> The following mixture (M-12) is prepared:

[0197] [Table 22] c ) Value when cooled

[0198] <Mixture example 13> The following mixture (M-13) is prepared:

[0199] [Table 23] c ) Value when cooled

[0200] <Study example 1> A capacitor containing two glass substrates with ITO electrodes is filled with a 110 μm layer of dielectric consisting of the medium of Mixing Example 1. Using a 10 Hz AC voltage, a capacitance of 1.41 μF is determined. The resulting relative dielectric constant (ε r ) is 4.2·10 4 It is.

[0201] <Device example 2> Preparation: A capacitor is prepared that contains two glass substrates (25 mm x 35 mm) with ITO electrodes spaced 750 μm apart. The two long side edges are sealed with a combination of UV resin and a thin glass tube that acts as a spacer. An electrical connection between the two ITO electrodes and a voltage source is made through the glass edges. With the glass substrates in a vertical position, one of the open sides of the capacitor is placed in a bulk reservoir of the LC medium of mixture example 1. N f -The LC medium fills the open space between the substrates, up to the level of the bulk liquid. The glass is marked with a vertical length scale starting from the meniscus of the liquid medium.

[0202] Electromechanical operation (DC): The device is supplied with voltages of 10V, 20V, 30V and 40V DC. The level of the medium in the capacitor rises against gravity until it reaches a new equilibrium position. The final level reached by the LC medium is proportional to the voltage employed. The initial vertical rate of filling is also positively correlated with the applied voltage (Table).

[0203] Table. Capacitor filling time versus applied voltage (DC)

[0204] [Table 24]

[0205] Temperature Dependence and Comparison Devices The device was operated at 20° C. and 50° C. At 50° C. the LC medium of the device was in the conventional nematic state (non-ferroelectric). Operation at 20° C. was as described above, while at 50° C. there was no visible change in the level of the LC medium when a voltage of 40 V was applied.

[0206] Non-ferroelectric nematic liquid crystal media do not respond to electrical signals as their electromechanical response is several orders of magnitude smaller.

[0207] <Device example 3> For this setup the device of device example 2 is maintained, but the electrical signal is changed.

[0208] Electromechanical operation (AC): The device of Device Example 2 is supplied with an AC (5Hz / 20Hz) voltage at 80V. The device fills at a slower rate than with a DC voltage.

[0209] Although the device could adapt to changes in the polarization of the power supply, frequent commutation reduces the net power conversion.

[0210] <Device Example 4> Piston Actuator The piston machine according to Fig. 2 is filled with a medium according to mixture example 1. The piston moves towards an electrode having an electric potential.

[0211] detail: The setup is similar to that of figure 2. An amount of about 1 g of medium according to mixture example 1 is filled into a flat container consisting of a thin glass plate sealed at the edges.

[0212] The container is suspended vertically from above by a long thread and placed at the interface between two pairs of flat electrodes that fit snugly to the thickness of the container. When a voltage (40V) is applied to one pair of electrodes, the force of the electric field on the dielectric causes the container to move towards the electrodes. When the electrodes are grounded, the container retracts to its starting position. By exchanging electrical signals and grounding the two pairs of electrodes, the container can be moved from one electrode to the other.

[0213] 100Vcm -1 In an electric field of 1 cm diameter 2 42000 epsilon r For a piston with a dielectric of 0.01 mm (parallel to the electric field), the force is approximately 2·10 -3 It's N.

[0214] <Device Example 5> Deformation of piston actuator Electromechanical transducer with a piston according to FIG. 3 Instead of the LC filled container according to device example 4, a non-ferroelectric low ε r A piston (a thermoplastic) moves through the ferroelectric nematic LC medium between the capacitor plates. The electric field draws the medium in and pushes the piston out of the field.

[0215] detail: A flat plastic piece is loosely trapped in a closed container containing a ferroelectric nematic LC medium. The plastic part occupies about 40% of the container's volume and can move laterally. As shown in Figure 3, the container has two pairs of electrodes on its surface. Using a glass plate as the container, the movement of the plastic part can be observed. By applying an appropriate electrical signal to the electrodes (see device example 4), the plastic part can be moved from one pair of electrodes to the other, acting like a piston within the medium.

[0216] <Device Example 6> Circular motor according to Fig. 4a / 4b A motor according to the illustrated profile can be made by 3D printing a suitable thin-walled plastic part. The construction materials are chosen to be suitable for organic materials, but in most cases the solubility in high molecular weight highly fluorinated media as used herein is acceptably low. A disk-shaped rotor with a diameter of 6 cm with a sector-shaped cavity suitable for the LC medium is printed, filled with the medium of mixture example 1 and sealed. The section without the cavity is partly thermoplastic and air, due to the need for stability during rotation. The rotor profile is designed to be flat to prevent abrasion of the electrodes during contact. The rotor is placed on the axis, as close as possible with a small gap between the sectored electrode pairs. The electrodes are addressed with an alternating phase DC voltage of variable amplitude. Rotation is initiated by an external impulse. The rotation speed is determined by the frequency of the phase sequence of the voltage source.

Claims

1. 1. An electromechanical transducer comprising: two or more electrodes for generating an electric field within a spatial volume distributed between the at least two electrodes; and a dielectric material at least partially disposed within the spatial volume of the electric field between the at least two electrodes, However, the dielectric material is said to be able to take a spatially variable position relative to the electrodes, wherein the dielectric material comprises one or more liquid crystalline (LC) materials in a ferroelectric nematic phase; 1. An electromechanical transducer according to claim 1, wherein said ferroelectric nematic LC material comprises at least two compounds having the molecular structure of Formula I: 【Chemical 1】 (In the formula, A １ teeth, 【Chemistry 2】 represents A ２ teeth, 【Chemistry 3】 represents A ３ teeth, 【Chemistry 4】 or a single bond, R １ is an alkyl group having 1 to 12 C atoms (but in addition, one or more CH ２ The groups may be in each case independently of one another, such that the O / S atoms are not directly linked to one another, such as -C≡C-, -CF ２ -O-, -OCF ２ -, -CH=CH-, 【Chemistry 5】 or represents H, X is CN, F, CF ３ , -OCF ３ , -NCS, Cl, L １ is H or CH ３ and Z １ is CF ２ O or —(CO)—O— or a single bond; Z ２ is CF ２ O, —(CO)—O—, or a single bond.

2. 2. The electromechanical transducer of claim 1, comprising as a dielectric a liquid crystal medium comprising 10% by weight or more of one or more compounds of formula IA, 10% by weight or more of one or more compounds of formula IB, and 10% by weight or more of one or more compounds selected from formulae IC-1 to IC-3. 【Chemistry 6】 (In the formula, X １Ｂ represents -CN or -NCS, X １Ｃ is -CN, F, CF ３ , -OCF ３ , -NCS, SF ５ or O-CF=CF2, Z １Ａ and Z １Ｂ are each independently —(CO)—O— or —CF ２ represents —O— or a single bond, Z ２Ａ and Z ２Ｂ are each independently a single bond, —(CO)—O— or —CF ２ represents —O—, Z １Ｃ and Z ２Ｃ One of the two groups is —(CO)—O— or —CF ２ -O- and the other represents a single bond; L １Ａ , L １Ｂ and L １Ｃ are each independently H or CH ３ represents L ２Ａ is F or H, L ２Ｃ is F or H, 【Chemistry 7】 represents 【Chemistry 8】 represents In the ceremony, L ８Ｂ represents alkyl, alkoxy or alkoxyalkyl having 1 to 7 C atoms, 【Chemistry 9】 represents 【Chemistry 10】 represents m and n are 0, 1, or 2, provided that (m+n) is 1; R １Ａ , R １Ｂ and R １Ｃ are each independently an alkyl group having 1 to 12 carbon atoms (provided that in addition, one or more CH ２ The groups may be in each case independently of one another, such that the O / S atoms are not directly linked to one another, such as -C≡C-, -CF ２ -O-, -OCF ２ -, -CH=CH-, 【Chemistry 11】 -O-, -S-, -(CO)-O- or -O-(CO)-, provided that in addition one or more H atoms may be replaced by halogen.

3. 2. The electromechanical transducer of claim 1, wherein the LC material exhibits a ferroelectric nematic phase at a temperature between 10°C and 30°C.

4. The LC material has a relative dielectric constant ε of more than 15,000 at 20°C and 10 Hz. ｒ 2. The electromechanical transducer of claim 1, wherein:

5. The electromechanical transduction machine of claim 1 , wherein the machine is configured to convert an electrical signal into motion.

6. 10. The electromechanical transducer of claim 1, wherein the electromechanical transducer is a linear electromechanical actuator that converts an electrical signal into linear motion.

7. 10. The electromechanical transducer of claim 1, wherein the liquid dielectric material is confined within a container.

8. 2. The electromechanical transducer of claim 1, wherein a dielectric material is disposed within a flow path within the spatial volume, and the spatially variable position of the dielectric material corresponds to a flow of the dielectric material within the flow path.

9. 2. The electromechanical transducer of claim 1, wherein the machine is an electric motor that converts an electrical signal into circular motion.

10. 10. The electromechanical transducer of claim 1, which converts mechanical motion into an electrical signal.

11. 10. The electromechanical transducer of claim 1, wherein the transducer is a microelectromechanical system with a distance between two electrodes across a spatial volume of 1 mm or less, or is integrated with electronic structures on a semiconductor chip.

12. 10. Use of a liquid crystal material having a ferroelectric nematic phase as defined in claim 1 as a dielectric material for an electromechanical transducer, for a motor or for a generator.

13. 10. A method for preparing an electromechanical transducer, comprising inserting a liquid crystal medium as a ferroelectric material as defined in claim 1 into a defined spatial volume and attaching two or more electrodes, wherein the electrodes define a second spatial volume distributed between the at least two electrodes, and wherein a dielectric material is disposed in contact with or partially within the second spatial volume.

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