Ferroelectric smectic A phase material, device containing the material, and method of forming and using the same

Abstract

A ferroelectric smectic A (SmA F ) liquid crystal-forming fluid-containing volume, and methods of forming and using such devices are disclosed. Exemplary devices include one or more surfaces for applying an electric field to the volume and one or more electrodes thereon.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims priority to U.S. Provisional Application No. 63 / 354,991, filed on June 23, 2022, entitled FERROELECTRIC SMECTIC A PHASE MATERIALS, DEVICES INCLUDING THE MATERIALS, AND METHODS OF FORMING AND USING SAME, the content of which is hereby incorporated by reference herein.

[0002] Statement Regarding Federally Sponsored Research or Development This invention was made with government support under grants No. DMR2005170 and DMR1710711 awarded by the National Science Foundation of the United States. The government has certain rights in this invention.

[0003] This disclosure generally relates to devices including ferroelectric liquid crystal materials. More particularly, this disclosure relates to devices including ferroelectric smectic A liquid crystal forming materials.

Background Art

[0004] Ferroelectricity in liquids was predicted in the 1910s by P. Debye and M. Born, who applied the ferromagnetic Langevin - Weiss model to the orientation order of molecular electric dipoles. In recent years, there has been growing interest in nematic ferroelectricity. Nematic ferroelectricity offers new opportunities in liquid crystal science and technology due to its unique combination of macroscopic polar order and fluidity. Furthermore, new phases of ferroelectric nematics may offer additional features desired for devices and applications. Therefore, improved devices and methods using ferroelectric nematic materials are desired.

[0005] The discussion of the problems and solutions described in this section is included in this disclosure only for the purpose of providing context for the disclosure, and should not be construed as an admission that some or all of the discussion was known at the time the invention was made.

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] This abstract is provided to introduce various concepts. This abstract is not necessarily intended to identify key or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0007] Liquid crystal science grows in richness and applicability each time a new phase is discovered or created. The recent discovery of ferroelectric nematics was exciting and unexpected because it emerged in new molecules that are not structurally very different from many substances that have been studied over the past 100 years. Clearly, there remain important, sometimes seemingly magical secrets in the complexity of the structure and interactions of organic molecules. A fundamental question following the discovery of ferroelectric nematics was whether a nematic-related phase, the ferroelectric smectic A, which is obtained when molecules spontaneously slide to form a planar layer of flow perpendicular to the long axis of the molecules, could also exist. Here, such a phase is reported, and devices containing such a phase and methods of using the phase are disclosed.

MEANS FOR SOLVING THE PROBLEMS

[0008] Embodiments of the present disclosure relate to devices containing a smectic A, a new liquid crystal phase in the ferroelectric nematic region. The smectic A F is included. The smectic A Fis a phase of small polar rod-like molecules that form a two-dimensional fluid layer with approximately average molecular length separation. The phase is uniaxial with a molecular director that is the local average major axis orientation perpendicular to the layer plane, and is ferroelectric with a spontaneous electric polarization parallel to the director. As will be discussed in more detail below, polarization measurements show nearly complete polar order of the longitudinal molecular dipoles of about 10 Debye, and a hysteretic polarization reversal is observed with a coercive force of about 2×10 5 V / m. The SmA F phase appears upon cooling in two binary mixtures of partially fluorinated mesogens: nematic (N)-smectic Z A (SmZ A )-ferroelectric nematic (N F )-SmA F phase sequence shown by 2N / DIO, and in N-SmZ A -SmA F phase sequence shown by 7N / DIO.

[0009] Various embodiments of the present disclosure relate to devices comprising a ferroelectric smectic A (SmA F ) liquid crystal forming fluid, and methods of using and forming the devices. Examples of the present disclosure may be described below, including the claims originally filed and incorporated herein by reference.

[0010] According to an exemplary embodiment of the present disclosure, a device comprises a ferroelectric smectic A (SmA F)It includes a volume containing a liquid crystal-forming fluid and means for containing said fluid. The fluid contains molecules organized in a layer. The molecules have one or more electric dipoles. The molecules form (e.g., spontaneously) a ferroelectric polarization density, said polarization density includes a non-zero local one-directional average orientation of said dipoles, said polarization density includes a magnitude and a vector direction in said volume, and said vector direction is locally perpendicular to said layer. According to an example of the present disclosure, the device includes one or more electrodes for applying an electric field to said volume. As described herein, the electrodes can be formed from any suitable conductive material such as gold, copper, aluminum, indium tin oxide (ITO). In some cases, an electromagnetic field can propagate within said volume, said electric field changes the magnitude of said polarization density, thereby causing a change in the electromagnetic field. In some cases, said electric field can cause a change in the vector direction of said polarization density, thereby causing a change in the electromagnetic field. In some cases, said electric field can cause a change in the vector direction and / or magnitude of said polarization density, thereby causing a change in the physical movement or shape of said volume. According to a further example, the device can include one or more electrodes for measuring a potential or current within said volume, said potential and / or current is generated by a change in said polarization density, and said change is due to a fluctuation in stress within said volume or a change in the shape of at least a part of said volume. In some cases, the device can thermally generate a charge density, said device includes one or more electrodes for measuring a potential or obtaining a current within said volume, said potential and / or current is generated by a change in said polarization density, and said change in said polarization density is caused by a change in the temperature of said volume. Said volume can be contained between parallel planes. The electric field may be applied parallel to the surface. The polarization density and / or the electromagnetic field may be parallel to said surface. According to various examples of the present disclosure, the volume contains two or more distinct molecules.In accordance with these and other embodiments, the molecules include features suitable for stabilizing a ferroelectric smectic A phase that include one or more of the following: (1) a rod-like shape having a molecular major axis suitable for ordering smectic A liquid crystals, (2) a substantial net dipole of the molecule parallel to the molecular major axis that stabilizes the head-to-tail chain structure of the rod-like molecules, (3) a molecular minor component along the molecular length that provides alternating-sign local charges distributed along the molecular major axis, (4) a minimal flexible tail that allows dipole charges to interact but provides sufficient flexibility to suppress crystallization, and (5) side groups that control the relative positions along the director of the side-by-side molecules to promote their polar order.

[0011] In accordance with a further example of the present disclosure, the device is a volume that includes ferroelectric smectic A (SmA F ) liquid crystal-forming molecules, the volume including a SmA F liquid crystal phase, the SmA FA volume including a liquid crystal phase that contains a vector orientation field of electric polarization density throughout the entire volume, and one or more materials including one or more surfaces in contact with the volume, wherein the one or more surfaces are configured to impart a favorable surface polarity to molecules, and the favorable surface polarity controls the vector orientation at the interface with one or more surfaces. The one or more materials may include a first material including a first surface in contact with the volume and a second material including a second surface in contact with the volume. The favorable surface polarity of the molecules may include, for example, a component that is locally perpendicular to at least one of the one or more surfaces and directed away from it, a component directed toward at least one of the one or more surfaces, or a component that is locally tangent to at least one of the one or more surfaces. The favorable surface polarity of the molecules can include components created by, for example, photolysis induced by irradiation of one or more surfaces, deposition of a material on the surface of one or more surfaces, deposition of a material on the surface of one or more surfaces where the deposition is oblique, etching of a material from one or more materials, etc. An exemplary device can further include one or more electrical connections for applying an electric field to the volume and / or a device for applying an electromagnetic field to the volume. The device is SmA F phase can further include dopant molecules dissolved in the phase. The dopant molecules may have a dipole moment, and the dipole moment is preferentially aligned by the vector orientation field of the SmA F phase adjacent to or in the vicinity of the dopant molecules. According to an example, the SmA F phase is a mixture of two or more distinct molecular species, and the SmA F phase may be a eutectic mixture.

[0012] According to yet a further example of the present disclosure, a method for controlling a three-dimensional favorable vector orientation of the polarization field of a SmA F liquid crystal at the interface surface with one or more materials is provided. The method is SmA FProviding a volume containing liquid crystal-forming molecules, providing a first material having a first surface in contact with the volume, and using the first surface to impart a favorable surface polarity to the molecules, the favorable surface polarity including controlling a favorable vector orientation of the molecules within the volume. The method may further include providing a second material having a second surface in contact with the volume. The favorable surface polarity of the molecules may be locally perpendicular to the surface and directed toward the surface, locally perpendicular to the surface and directed away from the surface, or locally tangential to the first surface (e.g., a specific favorable azimuthal orientation with respect to the surface normal). An exemplary method may further include applying an electric field to the SmA F phase. Dopant molecules may be dissolved in the SmA F phase as described above and elsewhere in this specification. According to an example, the SmA F phase is a mixture of two or more different molecular species, and the SmA F phase may be a eutectic mixture.

[0013] Also according to a further example, a device includes a volume containing liquid crystal-forming molecules and a first material including a first surface in contact with the volume, the first surface being configured to impart a favorable surface polarity to the molecules to control the vector orientation of the molecules within the volume at the interface with the first surface. The volume may include the SmA F phase. F

[0014] According to yet a further example of the present disclosure, a ferroelectric smectic A (SmA F ) material-containing material includes two or more molecular components. The material may include a mixture of a first molecule and a second molecule.

[0015] Also according to a further example, a method of forming a material having an adjustable SmA F phase includes mixing a plurality of molecules to form a mixture having the SmA F phase, wherein a particular one of the molecules induces a polar orientation order of one or more of the other molecules.​

[0016] Further in accordance with additional examples, the device includes a volume containing a ferroelectric smectic A (SmA F ) liquid crystal material, a dielectric layer covering a portion of the volume, and a charge-carrying substrate covering at least a portion of the dielectric layer, the volume including polarization charges proximate to the dielectric layer that are controllable by charges on the charge-carrying substrate and / or charges applied to the charge-carrying substrate. The device can include one or more additional dielectric layers covering the volume. In such cases, the device can include one or more additional charge-carrying substrates covering the one or more additional dielectric layers. In some cases, each surface bounding the SmA F liquid crystal includes a dielectric layer adjacent to the liquid crystal and a proximate charge-carrying substrate, and each surface has a finite capacitance and thus acts as a capacitor. In accordance with aspects of these embodiments, the polarization charges and molecular orientation of the SmA F liquid crystal on the inner (liquid crystal) side of the capacitor are controlled by changing the charges on the outer (substrate) side of the capacitor. In accordance with further aspects, the charges on the boundary surface and the resulting molecular orientation of the SmA F liquid crystal respond to an external electromagnetic or optical field, a chemical or electrochemical reaction, a biomolecular binding event, mechanical strain or shear, and fluid flow, among other external fields or other stimuli. The response to the external field or other stimuli is detected electrically and / or optically. Sensors, actuators and / or energy conversion devices can include the devices described in this paragraph and elsewhere in this specification. In some examples, the volume containing the SmA F liquid crystal is at least partially bounded by a surface having a spatially varying capacitance, and the molecular orientation in the SmA F material exhibits a spatially varying analog response to an applied voltage. In accordance with further examples, the volume containing the SmA F liquid crystal has a spatially varying capacitance and is at least partially bounded by a surface having electrodes patterned on a boundary substrate, and the molecular orientation in the ferroelectric nematic material exhibits a spatially varying analog response to the voltage applied to the patterned electrodes.

[0017] According to yet a further example of the present disclosure, the composite material includes a first porous material, and the pore volume of the material contains a ferroelectric smectic A (SmA F ) liquid crystal. The pore volume of the porous material may be substantially filled with the SmA F liquid crystal. The semiconductor structure can include a porous solid material, and the pore volume of the material contains the SmA F liquid crystal. The dielectric structure can include a porous solid electrical insulating material, and the pore volume of the material contains the SmA F liquid crystal. The capacitor can include an electrode and a dielectric medium, the dielectric medium includes a porous solid electrical insulating material, and the pore volume of the material contains the SmA F liquid crystal. The porosity of the porous material 104 can range from about 0.05 to about 0.4 or from about 0.5 to about 0.95. The pore diameter or average pore diameter of the pores of the porous material 104 can range from about 2 nm to about 50 nm, or from about 0.1 micrometer to about 10 micrometers. According to a further example, the dielectric medium includes the SmA F liquid crystal and a solid material, and the solid material is dispersed in the liquid crystal as particulate matter. The dielectric constant of the dielectric medium may be greater than 10, or may be about 2 to about 5000.

[0018] According to a further example, the dielectric medium includes the SmA F liquid crystal and a solid material, and the solid material is composed of ferroelectric or relaxor ferroelectric nanoparticles. According to yet a further example, the dielectric medium includes a dispersion of the SmA F liquid crystal and a solid material, and the dispersion is formed by phase separation.

[0019] According to a further example, the dielectric medium includes a dispersion of the SmA F liquid crystal and a solid material, and the dispersion is formed by photopolymerization. According to a further example, the dielectric medium includes a dispersion of the SmA F liquid crystal and a solid material, and the dispersion is stabilized by an amphiphilic molecular component.

[0020] According to a further example, the dielectric medium comprises an emulsion of a SmA F liquid crystal and a fluid material, the emulsion being stabilized by an amphiphilic molecular component. Exemplary suitable fluid materials include ionic liquids, dielectric liquids, and conductive liquids.

[0021] The device can include the composite material or dielectric medium described herein. The device can include, for example, an energy storage device (e.g., an energy conversion device), an information storage and processing device, an actuator, a sensor, an electrocaloric device, or a device for the conversion of electrical to mechanical energy, such as by an electromechanical effect.

[0022] According to a further example of the present disclosure, the device is a volume containing ferroelectric smectic A (SmA F ) liquid crystal-forming molecules, the volume including a SmA F liquid crystal phase, the SmA F liquid crystal phase including a bipolar SmA F vector orientation field of liquid crystal-forming molecules, the bipolar molecules having a finite first hyperpolarizability β, and one or more electrical connections for applying an electric field to the SmA F liquid crystal-forming molecules.

[0023] According to a further additional example, the device is a volume containing ferroelectric smectic A (SmA F ) liquid crystal-forming molecules, the volume including a SmA F liquid crystal phase, the SmA F liquid crystal phase including a bipolar SmA F vector orientation field of liquid crystal-forming molecules, the bipolar molecules having a finite first hyperpolarizability β, and one or more materials including one or more surfaces in contact with the volume, the one or more surfaces being configured to impart a favorable surface polarity of SmA F liquid crystal-forming molecules, the favorable surface polarity controlling the vector orientation at the interface with the one or more surfaces.

[0024] Further according to additional examples, the volume contains ferroelectric smectic A (SmA F ) liquid crystal forming molecules, and the volume contains SmA F liquid crystal phase, and the SmA F liquid crystal phase contains a bipolar SmA F vector orientation field of liquid crystal forming molecules, and the bipolar molecules have a finite first hyperpolarizability β; SmA F one or more electrical connections for applying an electric field to the liquid crystal forming molecules; and one or more materials including one or more surfaces in contact with the volume, wherein the one or more surfaces are SmA F configured to impart a favorable surface polarity to the liquid crystal forming molecules, and the favorable surface polarity controls the vector orientation at the interface with one or more surfaces, the material.

[0025] The various devices described herein can be used, for example, as components of a photonic integrated circuit for electro-optic phase, amplitude, or polarization modulation of an electromagnetic field, second harmonic generation, and non-linear optical frequency mixing of an electromagnetic field including sum and difference frequency generation, non-linear optical terahertz (THz) electromagnetic field generation and / or sensing, non-linear optical frequency conversion.

[0026] Further according to additional examples, the material can contain SmA F fibers of liquid crystal and / or SmA F thin films of liquid crystal. Such materials can be incorporated into polymeric, amphiphilic, and / or composite materials containing solid components. Such materials can be functional fabrics or cloths. Electro-optic devices can be formed using such materials. Exemplary fibers can have a length of about 20 μm to about 100 μm, or about 1 mm to about 20 mm, and / or a cross-sectional dimension (e.g., diameter) of about 5 μm to about 40 μm, or about 100 μm to about 300 μm.

[0027] Also according to further examples, SmA FThe material containing liquid crystal includes bipolar molecules having a large first hyperpolarizability β, the bipolar molecules have a polar orientation order, and the polar orientation order controls the second-order nonlinear optical properties of the material.

[0028] These and other embodiments will be readily apparent to those skilled in the art from the following detailed description of specific embodiments with reference to the figures. The present disclosure is not limited to the specific embodiments disclosed. A more complete understanding of embodiments of the present disclosure can be derived by referring to the detailed description and the claims when considered in connection with the following exemplary figures.

Brief Description of the Drawings

[0029]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

DETAILED DESCRIPTION OF THE INVENTION

[0030] It is understood that the elements in the figures are illustrated for simplicity and clarity and are not necessarily drawn to scale. For example, some dimensions of the elements in the figures may be exaggerated relative to other elements to facilitate understanding of the illustrated embodiments of the present disclosure.

[0031] Specific embodiments and examples are disclosed below, but it is understood that the present invention extends beyond the specifically disclosed embodiments and / or their use, and obvious modifications and equivalents thereof. Accordingly, it is intended that the scope of the disclosed invention should not be limited by the specific disclosed embodiments described below.

[0032] The present disclosure generally relates to devices containing ferroelectric smectic A (SmA F ) liquid crystal forming fluids, and methods of forming and using the devices. In the present disclosure, any two numbers of a variable can constitute the executable range of the variable, and the indicated range can include or exclude the end points. Further, any value of the indicated variable (regardless of whether it is indicated by "about") can refer to an exact value or an approximate value, including equivalents, and in some embodiments can refer to an average value, a median value, a representative value, a majority, etc. Any value, such as a percentage, can include + / - 10 percent, or + / - 5 percent, or + / - 2 percent of that value. A direction (such as a normal or a tangent) may include, for example, + / - 10 degrees or + / - 5 degrees or + / - 2 degrees from such a direction. Further, in the present disclosure, the terms "comprising," "consisting of," and "having," and related words, in some embodiments, can independently refer to "typically or broadly comprising," "including," "essentially consisting of," or "consisting of." In accordance with aspects of the present disclosure, the defined meaning of a term does not necessarily exclude the ordinary and customary meaning of the term.

[0033] Next, referring to the figures, FIG. 1 shows the structure, phase sequence, and schematic diagrams of the liquid crystal phase behavior of the single components of 2N, 7N, and DIO, and their indicated mixtures. As described in more detail below, the relevant phases of rod-like molecules with an electric dipole moment on the axis are shown, and the dipole direction of the schematic molecule is indicated by its perpendicular shading. (A) Sketch of phase organization classified macroscopically into non-polar and polar types. The experiments reported below are not only the new SmA F phase, but also confirm the existence of the previously described normal dielectric nematic phase (N), antiferroelectric smectic Z phase (SmZ A ), and ferroelectric nematic phase (N F ). These phases appear upon cooling, and the general order with respect to T is shown in the shaded regions. Note that in the 7N / DIO mixture, the N F phase does not exist, and a direct transition from smectic Z to smectic A F is possible. The thick solid line indicates the smectic layer structure. The SmA F phase is spontaneously ferroelectric, and the polarization P is about 6 μC / cm 2and the polar order parameter p is about 0.9, which are equivalent to the values of the N phase of DIO and RM734. The polarization reversal is brought about by the movement of pure polarization reversal domain walls. The alternation of polarization for each antiferroelectric layer induces a modulation of the spread of the director in the SmZ phase, but the spread is suppressed in the ferroelectric N phase and the SmA phase. F phase values. The polarization reversal is brought about by the movement of pure polarization reversal domain walls. The alternation of polarization for each antiferroelectric layer induces a modulation of the spread of the director in the SmZ A phase, but the spread is suppressed in the ferroelectric N F phase and SmA F phase.

[0034] Figure 2 shows the X-ray scattering and polarized microscopy textures of the N F and SmA F phases in a 50:50% 2N / DIO mixture. (A) Typical non-resonant SAXS and WAXS obtained upon cooling from N F to SmA F . At the N phase of 57.9 °C, there is a nematic-like diffuse scattering arc with a peak along q F ≈ 0.27 Å z along n, which is derived from the head-to-tail correlation of the mixture molecules. (B) Radial intensity scans along the n, qz direction (the white line in (A)) at different temperatures. In the case illustrated, as the smectic layers are formed, the texture reorganizes in the capillary, so the scattering pattern rotates by 10° in the azimuthal direction. The smectic peak, which was initially diffuse, becomes slightly sharper upon cooling and a well-defined resolution-limited SmA -1 Bragg reflection appears along the n direction at T ≈ 56 °C, and this appearance is an indication of smectic ordering with the layer plane perpendicular to n. The scattering vector q F ≈ 0.267 Å ZAF corresponds to the SmA -1 layer spacing of 23.5 Å, which is close to the wt% average molecular lengths of DIO (23.2 Å) and 2N (23.4 Å). The SmA F layer spacing of 23.5 Å, which is close to the wt% average molecular lengths of DIO (23.2 Å) and 2N (23.4 Å). The SmA FThe peak positions are very close to those of the nematic peak, as expected in the orthogonal smectic phase. The polarized microscope images all show the 50:50 wt% 2N / DIO mixture in (C, D) a d = 3.5 μm thick antiparallel cell (subjected to antiparallel surface rubbing) and (E) a d = 3.5 μm thick parallel cell (subjected to parallel surface rubbing) in the absence of an applied magnetic field. (C) SmA F The phase grows by slow cooling from the upper part of this region of the cell at T ≈ 55 °C into irregular polygonal domains where the n and P of the layers are oriented parallel to the cell plates and are uniformly aligned throughout their volume. The existing N F is in a π-twisted state induced by the surface, and P follows the (antiparallel) buffering along the surface. This twisted state does not give a preferred bulk polarization orientation. As a result, the advancing SmA F domains are ambiguous in the choice of polarization alignment and appear as if P is locally aligned either along +z or along -z, as shown. (D) SmA F to N F Different parts of the cell observed upon heating from the SmA F phase to the N phase. In the steady state shown in D1, the SmA z domains generally expand along z to minimize the polarization space charge, and the domains are separated by melting grain boundaries and polarization-stabilized kinks (PSKs) sketched in the inset of (E), which mediate small changes in the orientation of P along z. In contrast, non-zero (∂P F / ∂y) does not generate polarization charge, allowing for neighboring domains where the sign of the P direction alternates with changes in y. Heating to N F causes the boundaries between these adjacent domains to change to spreading-bending walls (bright lines in D2, 3), which then expand into π-twisted domains that ultimately cover most of the cell (D4, 5). (E) In the parallel cell, a uniform monodomain forms upon cooling, and the n of the N F and SmA FIt is along the polar orientation preferred in the phase. The image shows the tissue around the bubbles extending through the thickness of the cell. The preferred orientation of P at the bubble boundary is the tangential direction. At the meridian of the bubble, this boundary condition is compatible with the uniform polarization preferred by the cell surface, but elsewhere, n, P twists inside the cell to conform to this boundary condition, and the cell has a yellow-green transmission color that does not disappear. This non-uniform state continues up to the curved dashed line above the bubble, where the director field returns to the preferred uniform state. These lines of polarization-stabilizing kinks are overall parabolic and have a local structure (shown in the inset) that minimizes the polarization charge while mediating the change in the orientation of P. As the SmAF grows, the elimination of layer twist and bend makes a wider region around the bubble become uniform, and the non-uniform region is limited to a small area near the bubble. The transmission remaining in the region in contact with the bubble is probably due to SmA F resulting from the dislocation of the layered structure. Scale bar: (C) 500 μm, (D) 200 μm, (E) 100 μm.

[0035] Figure 3 shows the X-ray scattering and polarized microscopy textures of the N F and SmA F phases in a 50:50% 7N / DIO mixture. (A) Typical non-resonant SAXS obtained by cooling from SmZ A to SmA F . In the SmZ A phase at 43.6 °C, the SAXS shows a diffuse scattering arc with a peak along n at q z of about 0.27 Å -1 , which is due to the head-to-tail correlation of the mixture molecules, a feature also observed in the diffraction pattern of DIO. (B) Radial intensity scans along the n, q z direction (white line in (A)) at different temperatures. As in the case of the 2N mixture, the scattering pattern rotates and spreads as the SmZ A layers are replaced by SmA F layers and the tissue reorganizes within the capillary. The scattering from the SmZ A layered structure is not visible here but is shown in Figure 4. Upon cooling, the diffuse peak becomes slightly sharper, and the SmZ y along q AThe peak of the layered structure weakens and disappears. At T ≈ 31 °C, as shown in the inset, a distinct resolution-limited Bragg reflection appears along q z which is a sign of smectic ordering where the layer plane is perpendicular to n. The scattering wavevector q ZAF ≈ 0.245 Å -1 is close to the wt% average molecular lengths of DIO (23.2 Å) and 7N (29.1 Å), corresponding to the SmA F layer spacing of 25.6 Å. The position of the SmA F scattering peak is very close to the position of the diffuse nematic peak, as expected in the orthogonal smectic phase. (C, D) Polarized light microscopy images of a antipolar cell with electrodes separated by 1 mm (dashed white line) to apply an in-plane field perpendicular to the buffering direction z and a d = 3.5 μm spacing. The planar-aligned SmZ A texture shows only a subtle change upon transition to SmA F . This is because the antiparallel buffering aligns the director but does not favor either of the antiferroelectric polarization directions, so that upon transition, the nanoscale antiferroelectric SmZ A layers expand in the z direction along the normal of the new layers and the polarization alternates along y in the SmA FIt is simply coarsened in the domain. The director remains uniform through this change, giving a very similar appearance to the two phases. However, when a small E field applied along y (C3 - 6) is applied, the directors of the opposite P stripes rotate in the opposite direction, moving away from extinction and generating an optical contrast that confirms their opposite polarities. The circular black regions are bubbles, which effectively shield the applied electric field of the adjacent liquid crystal and do not disrupt the original structure. (D) Annealing after such an electric field treatment gives a heterogeneous smectic fan texture (D1, 2). In the applied electric field, these domains reorient, buckle, and in a sufficiently large applied electric field, coarsen to form large domains where n, z, and P are all oriented perpendicular to the buffing direction and along the electric field (D3 - 5). Thus, during the reorientation induced by the electric field, n, z, and P appear to remain coupled, and the threshold is due to the elasticity and plasticity of the smectic lamellar structure. This threshold also gives rise to the appearance of the coercive force in the polarization hysteresis (Figure 6). N F The phase is easily reoriented by a weak drifting applied electric field on the electrode. However, in the SmA F phase, there is a threshold of the electric field for such reorientation, so the electric field effect is limited to the electrode gap. Scale: The electrode gap (white dashed line in C) is 1 mm wide.

[0036] Figure 4 shows the X-ray diffraction from the periodic density modulation of the SmZ A phase in the 7N / DIO and 2N / DIO mixtures. Panels (A)-(C) each show the complete SAXS image of the scattering intensity I(q) using the color scale shown in (C). The rectangular overlay shows I(q) using the color scale of (B) after histogram stretching, revealing the weak scattering peaks due to the modulation of the SmZ y layers along q A The director is aligned to the nematic phase by the magnetic field B, but due to the rearrangement of the sample in the capillary during cooling, the orientation of the SmZ A layers and the SmA F layers becomes somewhat heterogeneous. (A) At T = 36 °C, the 7N / DIO mixture has a SmZ y as proven by the scattering along q Ais in the phase. q parallel to the director z The diffuse peak along z is due to the molecular correlation between the ends of the short distance. SmZ A The peak position is |q y | = q M ≈ 0.105 Å -1 at, corresponding to an interlayer spacing d essentially independent of T M ≈ 0.60 Å. (B) When cooled to T = 31 °C, a weak first-order phase transition to SmAF begins, and sharp scattering is observed simultaneously from both the SmZ A layer and the SmA F layer, indicating that the SmZ A / SmA F phases coexist. The peak of SmZ A at this temperature appears as an extended arc. The SmZ A scattering disappears at a temperature about 0.5 °C lower than the onset of the SmZ A -SmA F transition, that is, there is a narrow range of T where peaks of both SmZ A and SmA F exist, and the inventors consider this to be due to the coexistence of the two phases in the first-order transition. (C) Diffraction from a 2N / DIO mixture at T = 71 °C in the center of the SmZ A phase region. (D) Radial scan of the scattering intensity along q A perpendicular to the director obtained by averaging I(q) over the range of q z including the SmZ -1 peak (δq z ≈ ±0.015 Å z ) around q y = 0 (white line in C and D). The low-temperature scan in (B) shows the SmZ y peak at q -1 ≈ 0.105 Å A and the SmA y scattering at q -1 = 0.245 Å F . The SmZ A peak is exceeded, but this intensity is orders of magnitude smaller than the SmA z scattering peak along q F .

[0037] Figure 5 shows π twist NF SmA replaced by a phase (needle-like vertical domains in A - C, bright blocks in D, triangular regions in F) F SmA in the domain (broad vertical band), in the cells of FIGS. 2C, D (cells with an antiparallel surface rubbing treatment and a d = 3.5 μm spacing) F Showing the response of the tissue to the electric field and frustration. Twisted N F Since N does not bias polarization preference, either of the two domains of P should spontaneously appear. (A - C) This may be tested by applying a lateral in - plane electric field E (substantially perpendicular to n and P) to a region having domains with an overall - ly - oriented director. The macroscopically uniform polarization within the domain is verified by the oppositely - induced rotations in (A) and (C). (D, E) Twisted N F The rhombic inclusions of N mediate the up - down pair reversal (D) or termination (E) of the SmA domain. As shown in FIG. 2(E), the white domain boundaries of E are polarization - stabilized kinks (PSKs), which are local realignments of P stabilized by the attraction of sheets of opposite - signed polarization charges. F

[0038] FIG. 6 shows the I(t)-V(t) characteristics of the 2N / DIO mixture as a function of temperature by a 30 V peak - amplitude, 8 Hz triangular - wave voltage (white triangular trace) applied to a d = 17 μm ITO sandwich cell having a bookshelf - like layered structure in the smectic phase. The plot is N→SmZ A →N F →SmA F showing the current response during the cooling scan. In the N phase (T>84 °C), the current shows only an ionic peak following the sign change of V(t). SmZ A phase (84 °C>T>68 °C), two polarization peaks are seen during this half - cycle of the applied voltage, with the area increasing and occurring at a smaller voltage upon cooling. This is typical antiferroelectric behavior, and the peaks indicate a transition at a finite voltage between an electric - field - induced ferroelectric state and an equilibrium antiferroelectric state. N F ​In this phase, the reorientation mediated by the Goldstone mode seems to be "thresholdless", the inversion of P generates a current peak at the zero crossing of V(t), and an ion peak follows for t > 0. The polarization measured in this phase is equivalent to that of pure DIO. SmA F In this phase, the ionic current disappears, and a polarization inversion peak occurs at a positive voltage corresponding to the coercive force Ec, which is shown as an example at T = 34 °C (the vertical arrow starting from the right peak of the 34 °C trace is connected to the horizontal arrow terminating on the right side of the applied electric field axis). The temperature sequence of the I(t) curve is 135, 130, 125, 120, 115, 110, 105, 100, 95, 93, 91, 89, 87, 85, 83, 81, 79, 77, 75, 73, 71, 69, 67, 65, 63, 61, 59, 57, 55, 53, 51, 49, 47, 45, 43, 41, 39, 38, 37, 35 and 34 °C. (B) The polarization value P(T) [white circles] was obtained by integrating the current. SmZ A In this phase, since the polarization current generated following each zero crossing of V(t) overlaps with the ionic current, in this case, P(T) is obtained by doubling the area of the current peak that occurred before the zero crossing. The coercive force Ec is also shown as a function of T [solid line symbols]. Generally, due to the shielding by the polarization charge, the electric field is very small in the ferroelectric phase, so N F and SmA F Note that no ion peak is observed in.

[0039] Appropriate ferroelectricity in liquids was predicted by P. Debye and M. Born in the 1910s. They applied the Langevin - Weiss model of ferromagnetism and proposed a phase transition in the liquid state where the order transition is the spontaneous polar orientation of molecular electric dipoles. In 2017, a century later, two groups independently reported new nematic phases in strongly bipolar mesogens, the "extended nematic" of molecule RM734, and the "ferroelectric - like nematic" phase of molecule DIO shown in Fig. 1(B), in addition to the typical nematic (N) phase. These nematic phases were then shown to be ferroelectric in both RM734 and DIO, and it was demonstrated that they are the same phase in these two materials. This new phase, the ferroelectric nematic (NF ) is a uniaxially symmetric and spatially homogeneous nematic liquid in which the polar ordering of its longitudinal molecular dipoles is ≒> 90%. The recently observed related new phase is a helical ferroelectric N obtained by chiral doping RM734, DIO or their homologs, or by introducing a chiral tail into the molecular structure F . DIO also shows an additional phase found between N and N F and the inventors recently characterized this as the smectic Z A and also showed that this is also new: a density-modulated antiferroelectric that contains pairs of layers about 9 nm thick with alternating polarizations and shows a lamellar order with a repeat of about 18 nm with the director and polarization oriented parallel to the layer plane. Although specific molecules are described herein, it should be noted that the present invention is not limited to such examples unless otherwise specified

[0040] Here, a smectic A, another new phase in the ferroelectric nematic region, is a uniaxial lamellar phase with a director perpendicular to the layer and a spontaneous polarization along the director F is introduced. FIG. 1 shows a schematic diagram of the phases considered here, macroscopically classified into non-polar and polar types, together with the molecular structures and phase sequences of the mesogens used in the mixtures. FIG. 1(A) shows the macroscopically non-polar normal dielectric nematic (N) phase and smectic A (SmA) phase, the ferroelectric nematic (N F ) phase and the ferroelectric smectic A (SmA F ) phase, and the antiferroelectric SmZ A phase are sketched, and the light and dark shading of the molecules in the schematic diagram indicates their dipole symmetries. The SmAF phase was observed in 50:50 wt% AUUQU2N / DIO (2N / DIO) and AUUQU7N / DIO (7N / DIO) mixtures, and other weight ratios may also be suitable. The shaded regions in FIG. 1(A) show the general phase sequence (Iso → N → SmZ A → N F → SmA F→X), and it should be noted that some phases may be missing in a given component or mixture. For example, none of the single components exhibit the SmA F phase, and the 7N / DIO mixture does not have the N F phase. The first intermediate phase that appears when either a component or a mixture is cooled from isotropic is the conventional dielectric nematic (N) phase, which is also considered a normal dielectric in the current context. All of these are cooled from the N phase to the antiferroelectric smectic Z (SmZ A ) phase.

[0041] The 2N / DIO mixture first transitions to the N F phase, and upon further cooling, it transitions to SmA F , while 7N / DIO transitions directly to SmA F . This allows for a comparative study of both the N F →SmA F and SmZ A →SmA F transitions. The latter is characterized by the disappearance of the SmZ A layered structure parallel to the director and the simultaneous formation of the SmA F layered structure perpendicular to the director in the absence of a director / polarization reorientation.

[0042] In contrast to the conventional dielectric smectic A phase, the ferroelectric smectic A phase exhibits a macroscopic polarization P, and the polarization of all layers is oriented in the same direction along the director n perpendicular to the layer plane. The phase is uniaxial and has a high degree of polar order (polar order parameter p > 0.9). In regions with a continuous smectic layered structure, domains of opposite polarization separated by polarization reversal walls (sketched in Fig. 1(A)) are observed.

[0043] This ferroelectric phase differs from some of the previously described phases of uniaxial "polar smectic" which include the single-layer ordinary dielectric SmA1, the partial bilayer SmAd, the antipolar bilayer SmA2 phase, and various polarization modulation phases (Sm, Sm, etc.) of bipolar molecules in that they all have a net average polarization of zero. Tournilhac and co-workers initially claimed to observe a macroscopic polarization perpendicular to the layers of the low molecular weight smectic A phase based on evidence of piezoelectric and non-linear dielectric behavior, but subsequent X-ray scattering studies revealed smectic unit cell doubling, leading to the conclusion that the phase in question is a SmAd-type bilayer smectic and that the observed electrical effects are manifestations of bilayer antiferroelectricity. SmA F also differs from the orthorhombic polar smectic phases exhibited by some bent-core mesogens, forming a biaxial smectic with the spontaneous polarization oriented parallel to the smectic layers. Exemplary embodiments X-ray scattering - X-ray diffraction, polarized microscopy, and polarization measurement studies of the single molecular components DIO and 2N, 7N shown in Figure 1(B) were previously performed. Here, the two-component mixtures of 2N / DIO and 7N / DIO are focused on. All observations show that the N, N F SmZ A and SmA F phases exhibit common experimental characteristics, indicating that they appear to be the same phase in different materials: the N phase is a homogeneous uniaxial nematic phase, and the N F phase is a homogeneous uniaxial nematic phase with a macroscopic polarization along the nematic direction, and SmZ A is the same bilayer antiferroelectric phase in all components and mixtures, with d M ≈90 Å for DIO, d M ≈81 Å for the 2N / DIO mixture, and d M ≈60 Å for the 7N / DIO mixture. The period of the antiferroelectric polarization alternation per layer is 2d M .

[0044] Here, in all cases SmA FDescribe the LC behavior of 50:50% 2N / DIO and 7N / DIO mixtures shown. The inventors have found that these mixtures have (i) a SmA with a smectic layer spacing close to the average molecular length F similar SAXS from a layered structure, (ii) similar uniaxial birefringence, (iii) similar SmA-like optical textures, (iv) similar responses of SmA to surface alignment conditions and applied electric fields F , and (v) similar SmZ A and SmA F polarization reversal dynamics. There is a difference in the way SmA F grows upon cooling, with 2N / DIO originating from the N F phase and 7N / DIO originating from the SmZ A phase, so the two mixtures are described separately, as this condition strongly affects the morphology of SmA F .

[0045] In SAXS and WAXS experiments, the mixture was filled into a thin-walled capillary with a diameter of 1 mm, and the director n (both arrows in Fig. 2(A)) was aligned by an external magnetic field B (arrow). SAXS and WAXS were non-resonant, and diffraction images of the sample were obtained in transmission using a microbeam with an energy of 16.1 keV and a beam size of 2 μm x 25 μm at the SMI beamline (12-ID) of NSLS II.

[0046] Typical SAXS and WAXS images obtained when cooling the 2N / DIO - 50:50% 2N / DIO mixture from the N F phase to the SmA F phase are shown in Fig. 2(A). In the N F phase at T = 57.9 °C, a nematic-like diffuse scattering arc with a peak in the azimuthal orientation, originating from the head-to-tail pair correlation of molecules along n, is observed, and the scattering vector q is along n. A line scan of the scattering intensity through these peaks is shown in Fig. 2(B). As seen in the inset of Fig. 2(B), the SmA F phase has a wavevector q z ≈ 0.271 Å -1 at T ≈ 56 °C, which is very close to the wavevector of the diffuse nematic peak.ZAF ≈ 0.267 Å -1 The first appearance of q z is heralded by the appearance of a new resolution-limited peak along q. This behavior is consistent with polarized microscopy observations and indicates a first-order phase transition from N F to SmA F . The corresponding interlayer spacing is d AF = 23.5 Å, comparable to the concentration-weighted average molecular lengths of DIO (23.2 Å) and 2N (23.4 Å). In the SAXS image, since there is no second-harmonic peak at q z = q ZAF / 2, it can be seen that there is no tendency for bilayer fluctuations or ordering in this mixture in the SmA F phase. The WAXS diffraction image in Fig. 2(A) shows second-harmonic scattering from the layers at 2q ZAF ≈ 0.53 Å -1 . The azimuthal mosaic distribution of the full width at half maximum of n in a magnetically aligned sample is initially about 5°. The scattering pattern rotates in the SmA F phase upon cooling due to dynamic tissue rearrangement in the capillary, and at low temperatures, there is some detectable scattering from the layered structure at all azimuthal angles because the magnetic torque is not strong enough to maintain the alignment of the more rigid smectic layers.

[0047] Typical SAXS diffraction images obtained when cooling a 7N / DIO - 50:50% 7N / DIO mixture from the SmZ A phase to the SmA F phase are shown in Figs. 3(A) and 4. The SmA F scattering is qualitatively similar to that of the 2N / DIO mixture. In the SmZ A phase at T = 43.6 °C, SAXS shows a diffuse nematic-like scattering arc with the scattering vector q having a peak along n, which is due to the head-to-tail pair correlation of the molecules along n||z. The radial line scan of the scattering intensity along n (the white line shown in Fig. 3(A)) is shown in Fig. 3(B).

[0048] Similar to the 2N / DIO mixture, the SmA F phase has q zcharacterized by a new resolution-limited peak along, which peak is, as shown in the inset of Fig. 3(B), at T≒31 °C and is q, the maximum value of the diffuse nematic peak ZAF ≒0.245 Å -1 and first appears at. The corresponding interlayer spacing d AF = 25.6 Å is comparable to the concentration-weighted average molecular lengths of DIO (23.2 Å) and 7N (29.1 Å). In the SAXS image, no half-order peak of q z = q ZAF / 2 is seen, indicating again that there is no tendency to form a bilayer. As in the case of the DIO / 2N mixture, in the SmA F phase, the scattering pattern rotates due to the dynamic tissue rearrangement in the capillary with temperature change. In the SmA F phase, upon cooling, the effect of magnetic field alignment decreases, and the scattering arc broadens.

[0049] Finally, the equatorial Bragg spots of q A due to the density modulation by the smectic layer structure of SmZ y = q yM are shown in Fig. 4, which are observed in both the 2N / DIO and 7N / DIO mixtures but are relatively weak and thus not visible in Fig. 2(A) or Fig. 3(A).

[0050] By polarized optical microscopy, the director field n(r), and apart from its sign, P(r) can be directly visualized. These observations provide important evidence regarding the macroscopic ferroelectric ordering, uniaxial optical texture, and fluid layer structure of the SmA F phase of the 2N / DIO and 7N / DIO mixtures.

[0051] 7N / DIO - A 7N / DIO mixture of 50:50% was studied in a cell with d = 3.5 μm (antipolar cell) having planar electrodes on one surface separated by a 1 mm gap and subjected to an antiparallel surface rubbing treatment. In the N phase, as previously observed in the N phase of DIO, the LC formed a uniform, aligned monodomain with n along the buffing direction. As seen in Fig. 3 (C1, 2), in the 7N / DIO mixture without an applied electric field, there was little change in the sample appearance with temperature in these cells, and the nematic texture was maintained upon cooling to the SmZ A phase and SmA F phase. From SmZ A to SmA F transition, the SmZ A layers parallel to n disappear while new SmA F layers perpendicular to n are formed. The color of birefringence is uniform throughout the cell and changes only slightly during the N→SmZ A →SmA F cooling sequence, providing evidence that the phases are uniaxial or very weakly biaxial and that the optical anisotropy is nearly the same in all three phases. The uniaxiality of the N phase and the weak biaxiality of SmZ A have been demonstrated previously.

[0052] The SmZ A layers adopt a bookshelf shape, the smectic layers are perpendicular to the plane, and the director is aligned along the rubbing direction by the Rapini - Papoular type anchoring of the molecules. The transition from antiferroelectric SmZ A to ferroelectric SmA F phase is achieved by a coarsening process in which layers with the same sign of P coalesce into wider stripes of uniform polarization extending along z, resulting in SmA FIn this case, an irregular acicular ferroelectric domain structure with alternating polarization is formed. This process causes only subtle changes in the structure in the absence of an applied electric field (compare Figs. 3(C1 and 2)), but when an in-plane electric field perpendicular to n is applied, rotation of P in the opposite direction is induced in domains with opposite polarization, promoting and inducing coarsening of the domain pattern (Figs. 3(C3 - 6)). This electric field response becomes increasingly dramatic as the stripes coarsen from the nanoscale to the microscale.

[0053] When a weak electric field is applied for a long time, in the absence of a further applied electric field, the SmA F cell anneals and becomes long rectangular bookshelf domains with uniform birefringence and excellent extinction typical of a weakly oriented smectic A structure, as shown in Figs. 3(D1, 2). A sufficiently large transverse DC field can completely reorient the SmA F layer so that P and n align along E perpendicular to the buffering direction (Fig. 3(D5)). In the N F phase, this type of global electric field-induced reorientation has essentially no threshold and easily reverses with reversal of the applied electric field, but in the SmA F phase, there is a distinct threshold for switching and hysteresis in the response, which is evident from the polarization data in Fig. 5. This behavior can be understood by considering that the electric field-induced reorientation of a spatially uniform SmA F is only possible by the generation of a population of screw dislocation-like disclinations, which is an essentially non-linear process. The effect of this threshold is immediately evident in the electro-optical behavior of cells with in-plane electrodes. Under an applied electric field, these domains reorient, buckle, and for a sufficiently large applied electric field, coarsen to form large domains in which n, z, and P are all oriented perpendicular to the buffering direction along the electric field (Figs. 3(D3 - 5)). Thus, during electric field-induced reorientation, n, z, and P remain coupled, and the threshold appears to be due to the elasticity and plasticity of the smectic layer structure. Also, due to this threshold, a coercive force appears in the polarization hysteresis (Fig. 6). N FUsually, it readily responds to an in-plane applied electric field present anywhere within the cell, including on top of the metal or ITO electrodes, and even to a small fringing electric field far from the electrodes. In the SmA F phase, in contrast, this response becomes subthreshold and is excluded from these peripheral regions by an electro-optical effect limited to a designated active region of the cell where the electric field is strongest, as seen in FIGS. D3 - D5.

[0054] An interesting secondary observation is the lack of electric field response in the regions to the left and right of the bubble in FIG. 3 (C3 - 6). This "shielding" effect is a direct consequence of the strong ferroelectricity of the SmA F phase. A bubble located at the center of the gap between the electrodes results in a series connection of impedances: the left / right electrodes and the right / left boundaries of the bubble with SmA F as the filling medium, and the bubble with air as the filling medium. The regions with SmA F have a low electrical impedance due to the reorientation of a large polarization density, while the capacitance of the bubble is small, most of the applied voltage drops, and little electric field response remains in the adjacent LC.

[0055] A 2N / DIO - 50:50% 2N / DIO mixture was studied in cells with opposite polarities of d = 3.5 μm (subjected to anti - parallel surface rubbing) and cells with the same polarity of d = 5 μm (subjected to parallel surface buffing).

[0056] In the opposite - polarity cells, surface anchoring gives a twisted structure to the N F phase, in which the director / polarization fields n(r), P(r) rotate by π through the cell thickness. FIG. 2(C) shows a cell cooled through the first - order transition from N F to SmA F The twisted N F state (seen as broad diffuse domains at the bottom of these images) has a somewhat coarse texture, and the SmA F domains with uniform birefringence grow as smooth dark and bright bands or rectangular blocks at the top of the field of view. The uniformity of the birefringence color, and the SmA FFrom the observation that the domain can rotate between the crossed polarizers and be extinguished, the twist of the director is eliminated, and the main optical axis along n is SmA F It is shown that it is locally uniform through the cells in the F region and that n(r) is uniformly parallel to the plate. The growing SmA F Domains are not initially strongly aligned by the cell surface, probably because the polar domains are now amphiphilic with respect to the antipolar surface. The results of applying a weak probe electric field perpendicular to the director are shown in Figs. 5(A - C), confirming that each domain is homogeneously polar (black / white arrows) inside, oriented along the local director, some pointing up and some pointing down. Smectic A F When the bending and twisting of n(r) are eliminated by the layered structure and the spreading of n(r) is eliminated to remove the polarization charge, as shown in Fig. 2(D), a uniformly oriented SmA F Steady - state organization of the block is obtained, and Fig. 2(D) has distinct domain boundaries running parallel or perpendicular to n. The boundaries parallel to n (nearly vertical in these images) are polarization reversal walls such as those found in the N F Phase, while the boundaries perpendicular to n are the type of melting grain boundaries commonly found in the SmA phase that are not fully aligned by weak buffering, or polarization - stabilized kinks (PSKs) as sketched in the inset of Fig. 2(E). The change in the sign of P(r) across the horizontal boundaries is avoided to generate the maximum space charge, and the abrupt change in the orientation of P(r) at such positions is limited to less than 10°. In general, as seen in Figs. 2(D) and 3(D), long SmA F Domains of uniform polarization extending along the director tend to form. The internal change in orientation within the block is generally a few degrees and tends to bend within the director, which should be mediated by the edge dislocations of the SmA F Layered structure system.

[0057] Uniform SmA F A more detailed structure of the transition region mediating the growth from a uniform SmA F domain to a twisted region is shown in Figs. 5(D - F). Here, the rhombic N FThe remaining twisted domain forms a PSK domain boundary with a polarization direction in the neutral plane of the sample shown in Fig. 5(E), connecting to the surrounding uniform SmA F domain. A similar structure constitutes the zigzag SmA F -N F boundary line.

[0058] SmA F When heated again to the N F phase, the constraints of the layered structure are removed, so the polarization reversal walls are reconstructed into nematic splay-bend walls extending along the director, separated by uniform polarization regions (as seen in Figs. 2(D2), 3). The horizontal melting grain boundaries disappear in the absence of the layered structure, and the horizontal PSK lines can persist up to N F but then melt similarly, leaving only the splay-bend walls (bright lines in Figs. 2(D2), 3). Due to the anti-parallel boundary conditions, the initially uniform N F state is only metastable, and the essentially twisted core of the splay-bend wall functions as a nucleation site for forming a lower-energy twisted domain, which finally spreads to cover the entire area (Fig. 2(D5)).

[0059] In the homopolar cell, surface treatment stabilizes monodomains with n homogeneously aligned along the buffing direction. The texture and birefringence of these monodomains hardly change when cooled through the N - SmZ A -N F -SmA F phases and show excellent extinction between crossed polarizers for the N F and SmA F phases, except near the bubbles, as seen in Fig. 2(E). The first image corresponds to the non-uniform n(r) orientation imposed by the boundary conditions at the bubble boundaries, with a preferred uniform background N FShows how the director field is distorted, where the n(r) field is the tangential direction which requires only the bending of the director and minimizes the amount of space charge deposited at the LC / air interface. At the side of the bubble, the distortion of the director field is continuously relaxed with distance, and the director field eventually becomes indistinguishable from the surrounding uniform state. However, at the top and bottom of the bubble, the 90° angle mismatch between the circumferential P(r) and the uniform background is accommodated by a "break" in P(r) in the form of a polarization-stabilized kink sketched in the inset. The PSK has a minimum energy discontinuity in P(r), and the internal structure is determined by the balance of Frank elasticity and electrostatic interactions, with the latter appearing as the attractive force between sheets of polarization charges of opposite sign that stabilize the walls (shown directly above and below the walls in the inset). The orientation of the kink locally bisects the angle between the incident P(r) direction and the outgoing P(r) direction, resulting in a globally parabolic boundary between regions with uniform and circularly bent director fields having a minimum bulk polarization charge. Such a 2D parabolic texture is parallel to the boundary plate where P(r) is in its typically preferred orientation, N F is easily observable in the cell.

[0060] N F -SmA F In the transition, the region of uniform director orientation expands, which is a result of the emergence of the SmA layer structure. In the absence of edge and screw dislocations, the smectic excludes both the bending and twisting of n(r), and in the inhomogeneously aligned nonpolar smectic A, only layer structure defects in the form of focal conic domains are allowed as it only requires the spreading of n(r). However, in the polar SmA F phase, the spreading is also suppressed due to the associated polarization charges, and the tendency to form a uniform n(r) domain becomes stronger. Therefore, when the smectic layer is formed upon cooling, the curved director region near the bubble where both the bending and twisting of n(r) exist shrinks in size as shown in the second image of Fig. 2(E). The remaining curved and twisted director regions near the bubble should be accommodated by edge and screw dislocations in the smectic A layer structure.

[0061] Polarization dynamics and electric field-induced phase transitions - Polarization was measured in an ITO sandwich cell with a d = 17 μm book-shelf layer structure using a triangular wave of low frequency (8 Hz) and peak amplitude 30 V. The electrical responses of the 2N / DIO mixture are summarized in Fig. 6. At the start of the current-voltage cycle shown in Fig. 6(A), the applied voltage is strongly negative (V(t) ≒ -30 V), and at this point, ions are drawn to the cell surface. In the N phase (T > 84 °C), following a change in the sign of V(t), the current shows a bump, which is thought to be due to ions. This current is subtracted when calculating P. SmZ A In the SmZ phase (84 °C > T > 68 °C), as the voltage decreases, LC repolarization peaks appear, the area increases, and the center voltage V of these peaks FA decreases upon cooling, which is a behavior very similar to that of pure DIO. This is typical antiferroelectric behavior, and the peaks indicate a return to the antiferroelectric ground state at a finite voltage of the field-induced ferroelectric state. SmZ A In the SmA phase, since the polarization current interacts complexly with the ionic current each time the sign of V(t) changes, P(T) is obtained by doubling the area of I(t) on the left side of the t = 0 axis (before the zero-crossing of the applied voltage) where there is no ionic current. N F In the N phase, due to the reorientation and inversion of P mediated by the Goldstone mode, a current peak occurs at the zero-crossing of V(t), followed by an ionic peak at t > 0. P(T), interpreted as the area of the large peak, is found to be equivalent to that of pure DIO. SmA F In the SmA phase, the ionic current completely disappears, and the polarization reversal occurs after zero-crossing at a finite voltage corresponding to the coercive force Ec, plotted as solid symbols in Fig. 6(B) and schematically shown in the adjacent hysteresis loop.

[0062] The ferroelectric smectic A phase adds an exciting new dimension to the ferroelectric nematic region. Ferroelectric nematic, chiral ferroelectric nematic, and antiferroelectric smectic Z A have each opened unexpected doors to new soft matter science and technology, and here smectic A Fadds to this development. SmA F is a layered ferroelectric fluid and is the long-sought proper ferroelectric smectic A liquid, and its reorientable macroscopic spontaneous polarization has now been conclusively proven. N F from SmA F or SmZ A from SmA F to any of the SmA F to the transition is a first-order transition, rather subtle in cells with parallel polar surface anchoring, and its texture and many phase properties show continuity through the transition. In the presence of the long-range lateral molecular positions suggested by the ordering of the smectic A layers, the polarization that is about 90% saturated in N F remains so in SmA F . Since the lateral alignment is the most energy-intensive arrangement of similarly oriented dipoles, this is something of a conundrum. Materials and Methods The mixtures were studied using standard liquid crystal phase analysis techniques, including polarized transmission optical microscopy of LC textures and their response to electric fields, X-ray scattering (SAXS and WAXS), and techniques for polarization measurements and determination of electro-optic responses.

[0063] Materials - For these experiments, the DIO shown in Figure 1 was synthesized. The synthesis of AUUQU2N and AUUQU7N in Figure 1 followed the synthesis of AUUQU3N. X-ray Scattering - In SAXS and WAXS, the LC samples were filled into thin-walled capillaries with a diameter of 1 mm. The director n was aligned by an external magnetic field perpendicular to the beam. The diffraction data shown here were obtained at the SMI beamline of NSLSII using a photon energy of 16 keV (wavelength = 0.775 Å). At this wavelength, the desired range of the scattering vector (q < 0.5 Å -1 ) encompasses a small range of scattering angles (θ < 3°), whereby the Ewald sphere is perpendicular to the beam and the Ewald plane (q y , q z) can be approximated as. The SAXS and WAXS images of their mixtures with 2N, 7N, and DIO obtained upon cooling from the Iso phase to the nematic phase show strong diffuse scattering features at q z at about 0.25 Å -1 and q y at about 1.4 Å -1 respectively.

[0064] Electro - optics - To perform electro - optics measurements, the mixture was filled into a planar - aligned in - plane switching test cell having an alignment layer buffed in one direction on both plates. Cells with antiparallel buffing on plates separated by d = 3.5 μm and cells with parallel buffing on plates separated by d = 5 μm were used. The in - plane ITO electrodes were spaced 1 mm apart and the buffing was parallel to this gap. Such surfaces result in a quadrupole alignment of the director of N and SmZ A and a polar alignment of N F on each plate. The antiparallel buffing stabilizes a twisted configuration in the N F phase, generating a director / polarization field that is parallel to the plates and has a π - twist between the plates. The parallel buffing generates polar monodomains in the N F and SmA F phases.

[0065] Polarization measurements - The I(t) - V(t) characteristics of a 50:50 wt% 2N / DIO mixture were measured as a function of temperature for an AC electric field applied along n. The current response I(t) to a triangular wave V(t) of 8 Hz and peak amplitude 30 V was measured in an ITO sandwich cell with d = 17 μm having a bookshelf - like layered structure during the cooling scan of N→SmZ A →N F →SmA F .

[0066] Figure 7 shows a device 1300 according to various examples of the present disclosure. The device 1300 has a ferroelectric smectic A (SmA F)It includes a volume 1302 containing a liquid crystal forming fluid, and means (such as plates or surfaces 1304, 1306, etc.) for containing the fluid. The plates or surfaces can include, for example, polymers such as glass, PET, polycarbonate, etc. In the illustrated example, the device 1300 also includes one or more polymer layers 1310, 1312 and / or electrodes. An exemplary polymer for the layers 1310, 1312 includes polyimide. The surfaces 1311 and / or 1313 may be buffed, for example, using velvet.

[0067] Figure 8 shows another device 500 according to various embodiments and examples of the present disclosure. The device 500 includes one or more materials 504, 506 including a volume 502 and one or more surfaces 508, 510 in contact with the volume 502. The device 500 also includes one or more electrical connections 512, 514 that can be coupled to an electrode 1308 or an electrode such as the electrodes described later for applying an electric field to the volume, and a device 516 for applying an electromagnetic field or an electric field to the volume.

[0068] Figure 9 shows a cell deformation mode for electro-mechanical energy conversion. The ferroelectric smectic A material 906 is filled between the planar electrodes 902, 904 on the surfaces 901, 903, and the smectic layers 908 - 914 are parallel to the surfaces. (A, B) Current is generated by in-plane shear of the smectic layer. In (A), the polarization is parallel to the normal of the layer. The polarization charges on the surface balance the free charges on the electrodes. (B) Shear parallel to the electrodes causes reorientation of the polarization, reduces the polarization charge density on the surface, and causes a potential difference between the electrodes. In such a periodic shear system, a dynamic current can be generated through an external circuit. (C - E) Current is generated by bending of the smectic layer. In (C), there are three parallel electrodes on each surface. In the absence of mechanical deformation, the smectic layer has no strain and the free charges are uniformly distributed along the electrodes. Bending of the layer (D, E) causes accumulation of both bound charges and free charges in the central bent region. The imbalance of free charges between the neighboring electrodes can be used to generate a current through an external circuit.

[0069] There are three main types of distortion in the director field of liquid crystals: spreading, bending, and twisting. In conventional (nonpolar) smectic A materials, bending and twisting of the director are mostly suppressed because these distortions disrupt the preferred uniform layered structure. However, spreading of the director is allowed, and this distortion corresponds to bending of the layers and is achieved with little effect on the layer spacing.

[0070] In the ferroelectric smectic A phase, the presence of a large macroscopic ferroelectric polarization P enables new electromechanical effects and forms the basis for new electromechanical devices. The spreading of polarization P generates a polarization space charge ρ P = -∇·P, and the associated electrostatic energy is proportional to the square of the polarization (Eρ ∝ P 2 ). The electric field generated by the polarization charge increases the bulk electrostatic energy by an amount

[0071]

Number

[0072] (where k = (1 / 4πε) and ε is the dielectric constant of the liquid crystal) . Since the director n and P are collinear, this results in an effective stiffening of the response of the director field to the spreading distortion. The amplitude Pδn y and the periodic transverse modulation δP y of the polarization with wave vector q y (r) are assumed, and as a result, in our geometry ∇·P(r) = δP y (y)y = iq y P Z δn y , and the elastic energy density

[0073]

Number

[0074] (where K Sis obtained for the Frank splay elastic constant of the liquid crystal). This equation has the usual form of the Frank free energy density with the effective splay elastic constant K

[0075]

Number

[0076] given by. eff has the normal form. The inverse square dependence of the contribution of the polarization to the effective elastic constant on the wave vector indicates that the polarization term

[0077]

Number

[0078] (where

[0079]

Number

[0080] is the self-penetration length of the polarization) suggests that it becomes dominant in the case of. P = 6 μC / cm 2 In the case of, ξ p is about 0.1 nm, so this dominance persists up to the molecular length scale.

[0081] As a result, in the SmA F phase, in addition to suppressing bending and twisting, splay is also eliminated, and a kind of "soft crystal" is obtained. However, by applying sufficient mechanical stress, the deformation of the director field can be introduced by the work converted into electrostatic energy that can drive current in an external circuit. Two examples of such applications shown in Figure 9 are as follows.

[0082] First, in a cell having the shape of a parallel plate capacitor and with the smectic layer initially oriented parallel to the electrodes as shown in Fig. 9(A), the surface depolarization charges at the cell boundaries balance the free charges on the electrodes. Due to the liquid-like nature of the smectic layer, when the cell is sheared along a direction parallel to the layer as shown in Fig. 9(B), a low shear viscosity is ensured. This shearing action combines with the director field, causing an inclination of the polarization, and as a result, the surface depolarization charges are reduced. Due to the mismatch between the free charges and the surface depolarization charges, a voltage V = Pd(1 - cosθ) (where d is the cell thickness and θ is the inclination angle induced by the shear) is introduced across the electrodes. This electromechanical signal is characteristic of the SmA F phase and does not exist in conventional SmA without ferroelectric polarization. The sign of the induced voltage alternates depending on the shear direction, which is a response that can be useful as a dynamic mechanical-to-electrical energy converter.

[0083] In a second example, a liquid crystal material is similarly filled into a cell having the shape of a parallel plate capacitor with the smectic layer parallel to the electrodes. In this case, there are multiple electrodes on each surface, but again the surface depolarization charges are uniformly distributed along the cell boundaries and balance the free charges on the electrodes as shown in Fig. 9(C). As shown in Figs. 9(D) and (E), when sufficient stress is applied to bend the layer, polarization space charges appear in the liquid crystal, the density of the surface depolarization charges changes near the boundary electrodes, the balance between the free charges and the depolarization charges on the cell surface is disrupted, and a potential difference is generated between the electrodes (902, 904) near the same surface. The sign of the induced voltage alternates depending on the bending direction and can similarly be used for dynamic mechanical-to-electrical energy conversion.

[0084] Piezoelectricity is well-known and studied as an electromechanical effect in solid ferroelectric crystals. In crystalline materials, mechanical deformation is resisted by the lattice stiffness. Even a small deformation of the material requires a large stress to achieve. As a result, most of the work done on the material is stored as elastic energy within the crystal rather than being converted to electrostatic energy by coupling with the polarization. SmA FThe liquid crystal of the phase has a spontaneous polarization of a magnitude close to that of a solid ferroelectric, enjoying a basic advantage in that its rigidity is much lower, and the effective stress coefficient related to the induction of voltage by causing the spread of polarization is SmA F In the phase, it is much smaller than that related to generating an equivalent piezoelectric response in a solid. This suggests that the electro-mechanical energy conversion should be much more efficient in SmA F liquid crystals than in crystalline ferroelectrics.

[0085] Specific examples of the present disclosure A:SmA F Examples regarding devices: 1. A volume containing a ferroelectric smectic A (SmA F ) liquid crystal-forming fluid, and means for containing the fluid, the fluid containing molecules, the molecules being organized into layers, the molecules having one or more electric dipoles, the molecules having a spontaneously formed ferroelectric polarization density, the polarization density including a non-zero local one-directional average orientation of the dipoles, the polarization density including magnitude and vector direction in the volume, the vector direction being locally perpendicular to the layer, a device.

[0086] 2. The device according to example 1 for electrically controlling an electromagnetic field, the device including one or more electrodes for applying an electric field to the volume, an electromagnetic field propagating within the volume, the electric field changing the magnitude of the polarization density, thereby causing a change in the electromagnetic field.

[0087] 3. The device according to example 1 for electrically controlling an electromagnetic field, the device including one or more electrodes for applying an electric field to the volume, a controlled electromagnetic field propagating within the volume, the electric field changing the vector direction of the polarization density, thereby causing a change in the electromagnetic field.

[0088] 4. The device according to example 1 for generating an electrically driven motion, comprising one or more electrodes for applying an electric field to the volume, wherein the electric field changes the vector direction and / or magnitude of the polarization density, thereby causing a physical motion or a change in shape of the volume.

[0089] 5. The device according to example 1 for mechanical sensing, comprising one or more electrodes for measuring a potential or a current flow within the volume, wherein the potential and / or the current flow is generated by a change in the polarization density, and the change is due to a fluctuation in stress within the volume or a change in the shape of at least a part of the volume.

[0090] 6. The device according to example 1 for thermally generating a charge density, comprising one or more electrodes for measuring a potential within the volume or obtaining a current flow, wherein the potential and / or the current flow is generated by a change in the polarization density, and the change in the polarization density is caused by a change in temperature of the volume.

[0091] 7. The device according to any one of examples 1 to 6, wherein the volume is enclosed between parallel surfaces. 8. The device according to example 7, wherein the electric field is applied parallel to the surface. 9. The device according to example 7, wherein the polarization density is parallel to the surface.

[0092] 10. The device according to either example 7 or 8, wherein the electromagnetic field has a polarization parallel to the surface. 11. The device according to example 2 or example 3, wherein the electric field, the polarization density, and the polarization component of the electromagnetic field are along the same straight line.

[0093] 12. The device according to any one of examples 2, 3, or 7, wherein the electromagnetic field includes one or more of microwave, infrared, visible light, ultraviolet light, and X-ray light, and propagates within the device or is reflected from the device.

[0094] 13. The device according to example 1 for performing molecular dipole capture, wherein the polarization density generates local molecular-scale cavities, and the cavities bind to molecules having dipoles within the volume. 14. The device according to any one of examples 1 to 13, wherein the ferroelectric smectic A liquid crystal-forming fluid comprises a dimer, oligomer or polymer material.

[0095] 15. The device according to any one of examples 1 to 13, wherein the ferroelectric smectic A liquid crystal-forming fluid comprises an elastomer material. 16. The device according to any one of examples 1 to 13, wherein the ferroelectric smectic A liquid crystal-forming fluid comprises glass.

[0096] 17. A molecule having (1) a rod-like shape with a molecular major axis suitable for the ordering of a smectic A liquid crystal, (2) a substantial net dipole of the molecule parallel to the molecular major axis, the dipole stabilizing the head-to-tail chain structure of the rod-like molecule, (3) a molecular minor component along the molecular length providing alternating-sign local charges distributed along the molecular length, (4) a minimally flexible tail providing sufficient flexibility to allow the dipole charges to interact but suppress crystallization, and (5) one or more lateral groups controlling the relative position along the director of the side-by-side molecules to promote their polar order, the device according to any one of examples 1 to 16, comprising features suitable for the stabilization of a ferroelectric smectic A phase. 18. A method of using any of the devices of examples 1 to 17.

[0097] B: Examples related to polar alignment by a substrate: 19. A volume containing ferroelectric smectic A (SmA F ) liquid crystal-forming molecules, the volume comprising a SmA F liquid crystal phase, the SmA F liquid crystal phase comprising a vector orientation field of electric polarization density throughout the volume, and One or more materials comprising one or more surfaces that contact a volume, wherein the one or more surfaces are configured to impart an advantageous surface polarity to molecules, and the advantageous surface polarity controls the vector orientation at the interface with the one or more surfaces. One or more materials A device comprising.

[0098] 20. The device according to example 19, wherein the one or more materials comprise a first material comprising a first surface that contacts the volume and a second material comprising a second surface that contacts the volume. 21. The device according to example 20, wherein the second surface is configured to impart an advantageous surface polarity to molecules to control the vector orientation of the molecules within the volume at the interface with the second surface.

[0099] 22. The device according to any one of examples 19 - 21, wherein the advantageous surface polarity of the molecules is locally perpendicular to at least one of the one or more surfaces and includes a component directed away from at least one of the one or more surfaces.

[0100] 23. The device according to any one of examples 19 - 21, wherein the advantageous surface polarity of the molecules is locally perpendicular to at least one of the one or more surfaces and includes a component directed toward at least one of the one or more surfaces.

[0101] 24. The device according to any one of examples 19 - 21, wherein the advantageous surface polarity of the molecules includes a component that is locally in contact with at least one of the one or more surfaces. 25. The device according to example 24, wherein the component includes an advantageous azimuthal orientation specific to a surface perpendicular to at least one of the one or more surfaces.

[0102] 26. The device according to any one of examples 19 - 25, wherein the advantageous surface polarity of the molecules includes a component created via photolysis induced by irradiation of the one or more surfaces. 27. The device according to any of claims 19 - 25, wherein the advantageous surface polarity of the molecules comprises a component created by deposition of a material onto the surface of one or more surfaces.

[0103] 28. The device according to any of claims 19 - 25, wherein the advantageous surface polarity of the molecules comprises a component created by deposition of a material onto the surface of one or more surfaces, and the deposition is oblique.

[0104] 29. The device according to any of claims 19 - 25, wherein the advantageous surface polarity of the molecules comprises a component created by etching of a material from one or more materials. 30. The device according to any of claims 19 - 25, wherein the advantageous surface polarity of the molecules comprises a component created by etching of a material from one or more materials, and the etching is oblique.

[0105] 31. The device according to any of claims 19 - 30, further comprising one or more electrical connections for applying an electric field to the volume. 32. The device according to any of claims 19 - 31, further comprising a device for applying an electromagnetic field to the volume.

[0106] 33. SmA at the interfacial surface with one or more materials F A method for controlling a three - dimensional advantageous vector orientation of a polarization field of a SmA liquid crystal, comprising: SmA F providing a volume containing liquid - crystal - forming molecules, providing a first material having a first surface in contact with the volume, and using the first surface to impart an advantageous surface polarity to the molecules, the advantageous surface polarity controlling the advantageous vector orientation of the molecules within the volume A method comprising.

[0107] 34. The method according to claim 33, further providing a second material having a second surface in contact with the volume. 35. The method according to Example 33 or 34, wherein the favorable surface polarity of the molecule includes a component that is locally perpendicular to the surface and directed towards the surface.

[0108] 36. The method according to Example 33 or 34, wherein the favorable surface polarity of the molecule includes a component that is locally perpendicular to the surface and directed away from the surface. 37. The method according to Example 33 or 34, wherein the favorable surface polarity of the molecule includes a component that is locally in contact with the first surface.

[0109] 38. The method according to Example 37, wherein the component includes a specific favorable azimuthal orientation with respect to the surface normal. 39. The method according to any one of Examples 33 - 38, further comprising the step of applying an electric field to the SmA F phase.

[0110] 40. The device and method according to any one of Examples 19 - 39, further comprising dopant molecules dissolved in the SmA F phase. 41. The device and method according to Example 40, wherein the dopant molecule has a dipole moment, and the dipole moment is preferentially aligned by the vector orientation field of the SmA F phase adjacent to or in the vicinity of the dopant molecule.

[0111] 42. The device and method according to any one of Examples 19 - 41, wherein the SmA F phase is a mixture of two or more distinct molecular species. 43. The device and method according to Example 42, wherein the SmA F phase is a eutectic mixture.

[0112] 44. A device comprising a volume containing liquid crystal - forming molecules and a first material including a first surface in contact with the volume, wherein the first surface is configured to impart a favorable surface polarity of the molecules in order to control the vector orientation of the molecules within the volume at the interface with the first surface. F

[0113] 45. A device according to Example 44, comprising a phase with a volume of SmA F 46. A device according to Example 44 or Example 45, comprising any of the limitations of Examples 20-28 and 40-43

[0114] C: Examples related to mixtures: 47. A material comprising a ferroelectric smectic A (SmA F ) material containing two or more molecular components 48. A material according to Example 47, comprising a mixture of a first molecule and a second molecule 49. A method of forming a material having an adjustable SmA F phase, comprising the step of mixing a plurality of molecules to form a mixture having an SmA phase, and the step of inducing one or more polar orientation orders of other molecules by a specific molecule among the molecules F

[0115] D: Examples related to charge control devices: 50. A volume comprising a ferroelectric smectic A (SmA F ) liquid crystal material, a dielectric layer covering a part of the volume, and a charge-carrying substrate covering at least a part of the dielectric layer A device, wherein the volume contains polarization charges adjacent to the dielectric layer that can be controlled by charges on the charge-carrying substrate and / or charges applied to the charge-carrying substrate

[0116] 51. A device according to Example 50, further comprising one or more additional dielectric layers covering the volume 52. A device according to Example 51, further comprising one or more additional charge-carrying substrates covering one or more additional dielectric layers

[0117] 53. For each surface bounding the SmA F liquid crystal, it comprises a dielectric layer adjacent to the liquid crystal and a proximate charge-carrying substrate, and each surface has a finite capacitance and thus functions as a capacitor. A device according to any of Examples 50-52​​​

[0118] 54. SmA on the inner (liquid crystal) side of the capacitor F The device according to any one of Examples 50 to 53, wherein the polarization charge and molecular orientation of the liquid crystal are controlled by changing the charge on the outer (substrate) side of the capacitor.

[0119] 55. Charge on the boundary surface and the resulting SmA F The device according to any one of Examples 50 to 54, wherein the molecular orientation of the liquid crystal responds to an external electromagnetic field or optical field, chemical reaction or electrochemical reaction, biomolecular binding event, mechanical strain or shear, and external field or other stimuli including fluid flow.

[0120] 56. The device according to Example 55, wherein the response to the external field or other stimuli is electrically detected. 57. The device according to Example 55, wherein the response to the external field or other stimuli is optically detected.

[0121] 58. A sensor comprising the device according to any one of Examples 50 to 57. 59. An actuator comprising the device according to any one of Examples 50 to 57. 60. An energy conversion device comprising the device according to any one of Examples 50 to 57.

[0122] 61. SmA F A volume containing a liquid crystal is at least partially bounded by a surface having a spatially varying capacitance, said SmA F The device according to any one of Examples 50 to 57, wherein the molecular orientation in the material exhibits a spatially varying analog response to an applied voltage.

[0123] 62. SmA FA device according to any of Examples 50 to 57, wherein a volume containing a liquid crystal has a spatially varying capacitance and is at least partially bounded by a surface having electrodes patterned on a boundary substrate, and the molecular orientation in the ferroelectric nematic material exhibits a spatially varying analog response to a voltage applied to the patterned electrodes.

[0124] E: Examples related to composite materials: 63. A composite material comprising a first porous material, wherein the pore volume of the material contains a ferroelectric smectic A (SmA F ) liquid crystal.

[0125] 64. The composite material according to Example 63, wherein the pore volume of the porous material is substantially filled with SmA F liquid crystal. 65. A semiconductor structure comprising a porous solid material, wherein the pore volume of the material contains SmA F liquid crystal.

[0126] 66. A dielectric structure comprising a porous solid electrical insulating material, wherein the pore volume of the material contains SmA F liquid crystal. 67. A capacitor comprising an electrode and a dielectric medium, wherein the dielectric medium comprises a porous solid electrical insulating material, and the pore volume of the material contains SmA F liquid crystal.

[0127] 68. A dielectric medium comprising SmA F liquid crystal and a solid material, wherein the solid material is dispersed in the liquid crystal as particulate matter. 69. A dielectric medium comprising SmA F liquid crystal and a solid material, wherein the solid material consists of ferroelectric or relaxor ferroelectric nanoparticles.

[0128] 70. A dielectric medium comprising a dispersion of SmA F liquid crystal and a solid material, wherein the dispersion is formed by phase separation. 71. SmAF A dielectric medium comprising a dispersion of a liquid crystal and a solid material, wherein the dispersion is formed by photopolymerization.

[0129] 72. SmA F A dielectric medium comprising a dispersion of a liquid crystal and a solid material, wherein the dispersion is stabilized by an amphiphilic molecular component. 73. SmA F A dielectric medium comprising an emulsion of a liquid crystal and a fluid material, wherein the emulsion is stabilized by an amphiphilic molecular component.

[0130] 74. A device comprising the composite material or dielectric medium according to any one of Examples 63, 64 and 66 to 73. 75. The device according to Example 74, wherein the device is an energy storage device.

[0131] 76. The device according to Example 74, wherein the device is an energy conversion device. 77. The device according to Example 74, which is an information storage and processing device. 78. The device according to Example 74, which is an actuator, a sensor, an electrocaloric device, or a device for converting electrical energy into mechanical energy by an electromechanical effect.

[0132] F: Other examples: 79. A volume containing ferroelectric smectic A (SmA F ) liquid crystal-forming molecules, wherein the volume contains an SmA F liquid crystal phase, and the SmA F liquid crystal phase contains a bipolar SmA F vector orientation field of liquid crystal-forming molecules, and the bipolar molecules have a finite first hyperpolarizability β, a volume, and SmA F one or more electrical connections for applying an electric field to the liquid crystal-forming molecules and a device comprising the same.

[0133] 80. Ferroelectric smectic A (SmA F) A volume containing liquid crystal-forming molecules, wherein the volume has a SmA F liquid crystal phase, and the SmA F liquid crystal phase has a bipolar SmA throughout the volume F including a vector orientation field of liquid crystal-forming molecules, wherein the bipolar molecules have a finite first hyperpolarizability β, a volume, and one or more materials including one or more surfaces in contact with the volume, wherein the one or more surfaces have a SmA F configured to impart a favorable surface polarity of liquid crystal-forming molecules, and the favorable surface polarity controls the vector orientation at the interface with the one or more surfaces, one or more materials A device comprising.

[0134] 81. A ferroelectric smectic A (SmA F ) A volume containing liquid crystal-forming molecules, wherein the volume has a SmA F liquid crystal phase, and the SmA F liquid crystal phase has a bipolar SmA throughout the volume F including a vector orientation field of liquid crystal-forming molecules, wherein the bipolar molecules have a finite first hyperpolarizability β, a volume, SmA F one or more electrical connections for applying an electric field to the liquid crystal-forming molecules, and one or more materials including one or more surfaces in contact with the volume, wherein the one or more surfaces have a SmA F configured to impart a favorable surface polarity of liquid crystal-forming molecules, and the favorable surface polarity controls the vector orientation at the interface with the one or more surfaces, one or more materials A device comprising.

[0135] 82. A device according to any of Examples 79 - 81, used for electro-optic phase, amplitude, or polarization modulation of an electromagnetic field. 83. A device according to any of Examples 79 - 81, used for non-linear optical frequency mixing of an electromagnetic field including second harmonic generation and sum and difference frequency generation.

[0136] 84. A device according to any of Examples 79 - 81, for use in generating and / or sensing non - linear optical terahertz (THz) electromagnetic fields. 85. A device according to any of Examples 79 - 81, for use in non - linear optical frequency conversion.

[0137] 86. A device according to any of Examples 79 - 81, wherein the device is a component of a photonic integrated circuit. 87. SmA F A material comprising fibers of liquid crystal.

[0138] 88. SmA F A material comprising a thin film of liquid crystal. 89. A material according to either 87 or 88, incorporated into a composite material comprising a polymer, an amphiphilic and / or a solid component.

[0139] 90. A material according to any of 87 - 89, comprising a functional fabric or cloth. 91. A device based on a material according to any of 87 - 90, which is a sensor, an actuator and / or an energy conversion device.

[0140] 92. A device based on a material according to any of 87 - 89, which is an electro - optical device. 93. SmA comprising bipolar molecules having a large first hyperpolarizability β F A material comprising a liquid crystal, wherein the bipolar molecules have a polar orientation order, and the polar orientation order controls the second - order non - linear optical properties of the material.

[0141] The exemplary embodiments of the present disclosure described above are merely examples of embodiments of the present invention and do not limit the scope of the present invention. Any equivalent embodiments are intended to be within the scope of the present invention. In fact, in addition to the embodiments shown and described herein, various modifications of the present disclosure, such as alternative useful combinations of the described elements, may become apparent to those skilled in the art from the description. Such modifications and embodiments are also intended to be included within the scope of the appended claims. A:SmA FClaims regarding the device: Claims regarding the polarity alignment by the substrate:

Claims

Claim 1 A volume containing a ferroelectric smectic A (SmA Ｆ ) liquid crystal forming fluid, and means for containing said fluid, said fluid containing molecules, said molecules being organized in layers, said molecules having one or more electric dipoles, said molecules having a spontaneously formed ferroelectric polarization density, said polarization density including a non-zero local one-directional average orientation of said dipoles, said polarization density including magnitude and vector direction in said volume, said vector direction being locally perpendicular to said layer, a device. Claim 2 The device according to claim 1 for electrically controlling an electromagnetic field, wherein the device includes one or more electrodes for applying an electric field to the volume, an electromagnetic field propagates within the volume, the electric field changes the magnitude of the polarization density, thereby causing a change in the electromagnetic field. Claim 3 The device according to claim 1 for electrically controlling an electromagnetic field, wherein the device includes one or more electrodes for applying an electric field to the volume, a controlled electromagnetic field propagates within the volume, the electric field changes the vector direction of the polarization density, thereby causing a change in the electromagnetic field. Claim 4 The device according to claim 1 for generating an electrically driven motion, wherein the device includes one or more electrodes for applying an electric field to the volume, the electric field changes the vector direction and / or magnitude of the polarization density, thereby causing a physical motion or a change in the shape of the volume. Claim 5 The device according to claim 1 for mechanical sensing, wherein the device includes one or more electrodes for measuring the potential or current flow within the volume, the potential and / or current flow is generated by a change in the polarization density, and the change is due to a fluctuation in stress within the volume or a change in the shape of at least a part of the volume. Claim 6 The device according to claim 1 for thermally generating a charge density, wherein the device includes one or more electrodes for measuring the potential within the volume or obtaining a current flow, the potential and / or current flow is generated by a change in the polarization density, and the change in the polarization density is caused by a change in the temperature of the volume. Claim 7 The device according to any one of claims 1 to 6, wherein the volume is included between parallel surfaces. Claim 8 The device according to claim 7, wherein one / the electric field is applied parallel to the surface. Claim 9 The device according to claim 7, wherein the polarization density is parallel to the surface. Claim 10 The device according to any one of claims 7 or 8, wherein the electromagnetic field has a polarization parallel to the surface. Claim 11 The device according to claim 2 or claim 3, wherein the electric field, the polarization density, and the polarization component of the electromagnetic field are along the same straight line. Claim 12 The device according to any one of claims 2, 3 or 7, wherein the electromagnetic field includes one or more of microwave, infrared, visible light, ultraviolet light and X-ray light, and propagates through the device or is reflected from the device.

13. The device according to claim 1, for performing molecular dipole capture, wherein the polarization density generates local molecular-scale cavities, and the cavities bind to molecules having dipoles within the volume.

14. The device according to any one of claims 1 to 13, wherein the ferroelectric smectic A liquid crystal-forming fluid includes a dimer, oligomer or polymer material.

15. The device according to any one of claims 1 to 13, wherein the ferroelectric smectic A liquid crystal-forming fluid includes an elastomer material.

16. The device according to any one of claims 1 to 13, wherein the ferroelectric smectic A liquid crystal-forming fluid includes glass.

17. A molecule having (1) a rod-like shape with a molecular major axis suitable for the ordering of a smectic A liquid crystal, (2) a substantial net dipole of the molecule parallel to the molecular major axis, which stabilizes the head-to-tail chain structure of the rod-like molecule, (3) a molecular minor component along the molecular length that provides alternating-sign local charges distributed along the molecular major axis, (4) a minimal flexible tail that allows the dipole charges to interact but provides sufficient flexibility to suppress crystallization, and (5) one or more lateral groups that control the relative position along the director of the side-by-side molecules to promote their polar order, the device according to any one of claims 1 to 16, comprising features suitable for the stabilization of a ferroelectric smectic A phase.

18. A method of using any of the devices of claims 1 to 17.

19. A volume containing ferroelectric smectic A (SmA Ｆ ) liquid crystal-forming molecules, wherein the volume contains a SmA Ｆ liquid crystal phase, and the SmA Ｆ liquid crystal phase contains a vector orientation field of electric polarization density throughout the volume, a volume, and One or more materials including one or more surfaces in contact with a volume, wherein the one or more surfaces are configured to impart an advantageous surface polarity to molecules, and the advantageous surface polarity controls the vector orientation at the interface with the one or more surfaces. A device comprising.

20. The device according to claim 19, wherein the one or more materials include a first material including a first surface in contact with the volume and a second material including a second surface in contact with the volume.

Images