WO2021150571A1 - Light modulating device with polymer wall compartments and methods of making the same - Google Patents

Abstract

A light modulating device / layer is disclosed. A polymerizable precursor composition may contain a polymerizable reactive monomer component, a liquid crystal formulation, a polymerization inhibiting compound, a UV blocking compound and/or a photo-initiator is described. A light modulating layer is also described, the modulating layer having a plurality of polymer walls defining a plurality of compartments, the polymer walls disposed between a pair of transparent electrically conductive elements, and a light modulating compound disposed within the defined compartments. A method for making such light modulating device is also described.

Description

LIGHT MODULATING DEVICE WITH POLYMER WALL COMPARTMENTS AND METHODS OF

MAKING THE SAME

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 62/964,261, filed January 22, 2020, which is incorporated by reference herein in its entirety.

BACKGROUND

In the fenestration industry, smart windows are attractive alternatives to conventional mechanical shutters, blinds, or hydraulic methods of shading. Efforts have been made to optimize smart windows to control light waves, e.g. ultraviolet, visible and infrared light, from passing through windows. Such control may be to provide privacy, reduce heat from ambient sunlight, and control harmful effects of ultraviolet light.

Liquid crystals or other kinds of functional liquid phase materials may be used for light modulation in response to various external stimuli, such as thermal stimulus, UV light stimulus, electric field stimulus, magnetic field stimulus, etc. In large surface area devices, such as in windows, the vertical dimension (parallel to the vector of gravitational acceleration) may be several feet in diameter. In certain conditions, gravitational effects on a liquid crystal layer may dominate the capillary effect, depending on capillary cell gap width, surface tension, contact angle, etc. Additionally, window devices may be exposed to a broad range of environmental conditions, such as a broad range of temperatures. Light modulating liquid compositions may experience significant thermal expansion at elevated temperature and due to gravity may move downward, accumulating at the bottom of the device causing undesired "gravity mura" defects or even damage to the device. Polymer dispersed liquid crystal (PDLC) technology has been utilized to contain liquid crystals as droplets within a polymer matrix. However, PDLC devices have poor optical performance and such devices require relatively high driving voltage.

Responsive to these shortcomings, other approaches for compartmentalized liquid crystal layers have been described (See e.g., United States Patent Nos. 8,497,958; 8,330,902; 6,130,738, and United States Application Publication No. 2019/0155083). However, these may not satisfy the optical clarity requirements for display and/or smart window applications. In addition, these may not be utilizable in roll-to-roll fabrication processes necessary for high speed manufacturing requirements.

Therefore, there is a need for a light modulating device that may address any or all of the problems mentioned above having a high quality polymer wall structure formed in a controlled process and/or compatible with high throughput manufacturing requirements. Such a device may have better transparency in one of its states, improved viewing angles and low power consumption (for example, capable of battery powering).

SUMMARY OF THE DISCLOSURE

The current disclosure describes a light modulating device. In some embodiments, the light modulating device may be a selectively transparent window. In some embodiments, the light modulating device may be a display element. In some examples, light modulating device comprises a light modulating composition.

Some embodiments include a light modulating device comprising: a first transparent electrically conductive element; a second transparent electrically conductive element; a light modulating layer disposed between the first transparent electrically conductive element and second transparent electrically conductive element; wherein the light modulating layer comprises a plurality of compartments divided by polymer walls bonded respectively to and between the first transparent electrically conductive element and the second transparent electrically conductive element; and wherein the plurality of compartments comprise a liquid crystal compound.

Some embodiments include a polymerizable liquid crystal composition comprising: about 10 wt% to about 50 wt% of diffusing reactive monomer; about 90 wt% to about 50 wt% of liquid crystal compound; about 0.01 wt% to about 5.0 wt% polymerization inhibiting compound; about 0.01 wt% to about 5.0 wt% ultraviolet (UV) light absorbing compound; about 0.01 wt% to about 5.0 wt% photoinitiator compound; and about 0.01 wt% to about 5.0 wt% microsphere spacer beads.

Some embodiments include a method for making a light modulating device comprising: curing a polymerizable liquid crystal composition between a first transparent electrically conductive element and a second transparent electrically conductive element; wherein the polymerizable liquid crystal composition comprises a diffusing reactive monomer, a liquid crystal compound, a polymerization inhibitor compound, an ultraviolet inhibitor compound, a photoinitiator compound; and microsphere spacer beads; wherein curing the polymerizable liquid crystal composition causes the diffusing reactive monomer to be incorporated, by polymerization reaction, into polymer wall structures between the first transparent electrically conductive element and second transparent electrically conductive element; wherein the polymer wall structures incorporate at least 90 wt% of the diffusing reactive monomer and less than 10 wt% of the liquid crystal compound therein, wherein the polymer wall structures define a plurality of compartments therein; and wherein the compartments defined by the polymer wall structures contain a composition comprising less than 10 wt% of diffusing reactive monomer subunits and at least 90 wt% of the liquid crystal compound.

In some embodiments, a light modulating device comprises: a first transparent electrically conductive element; a second transparent electrically conductive element; and a light modulating layer disposed between the two transparent electrically conductive elements; wherein the light modulating layer comprises a polymerizable liquid crystal composition comprising: diffusing reactive monomer subunits; a liquid crystal compound; a polymerization inhibitor compound; a UV blocker compound; a photoinitiator compound; microsphere spacer beads; or any combination thereof. In some embodiments, the polymerizable liquid crystal composition further comprises a chiral dopant. In some embodiments, the light modulating layer may be disposed between the first and second transparent electrically conductive elements. In some embodiments, polymerization of the light modulating formulation forms a plurality of polymer walls that may be bonded respectively to and between the first transparent electrically conductive element and the second transparent electrically conductive element. In some embodiments, the polymer walls define plural compartments therebetween. In some embodiments, the polymer walls may comprise at least 90 wt% of the diffusing reactive monomer subunits and less than 10 wt% of the liquid crystal compound. In some embodiments, said reactive diffusing monomer subunits may have a diffusion coefficient determining the diffusion distance of the reactive monomer subunits from a position within the defined compartment along a path half the length of the defined compartment to a position defining a portion of the polymer wall within a given curing time. In some embodiments, the light modulating device may comprise compartments having a residual composition which may comprise at least 90 wt% of the liquid crystal compound and less than 10 wt% of the diffusing reactive monomer subunit. In some embodiments, the polymer wall may have a width of about 1 micron to about 100 microns. In some embodiments, the compartments defined by the polymer walls may have a lateral spacing, or width, of between 10 microns to about 2000 microns.

In some embodiments, the diffusing reactive monomer subunit comprises an acrylic monomer, such as 2-phenoxyethyl acrylate, acryloyl morpholine, acrylic acid, ethylene glycol diacrylate, or a combination thereof. In some embodiments, the liquid crystal compound is QYPDLC-8, MLC2132, or any combination thereof. In some embodiments, the polymerization inhibitor compound may be phenothiazine, N-nitroso-N-phenylhydroxylamine aluminum salt, or a combination thereof. In some embodiments, the UV-blocker compound is 2,5-bis(5-ferf- butyl-benzoxazol-2-yl)thiophene, UV-790, or a combination thereof. In some embodiments, the microsphere spacer beads have a diameter of about 1-20 microns, about 8-12 microns, or about 10 microns. Some embodiments include a method for making a light modulating device. In some examples, the method comprises disposing a polymerizable liquid crystal composition between a first electrically conductive element and a second electrically conductive element; growing a polymer wall structure between the electrically conductive elements by selectively curing the reactive monomer subunits. In some embodiments, the growing of polymer walls may comprise exposing an area to a curing radiation, and double-sided additive polymerization of the diffusing reactive monomer subunits within the area exposed to a curing radiation. In some embodiments, the method for growing the polymer walls comprises placing a photomask, having defined apertures therein, upon one of the substrates, wherein the apertures have a defined width and a defined spacing between them; applying photocuring radiation through the photomask apertures upon the polymer precursor composition for a period of time and intensity to cure the reactive monomers and form a plurality of polymer walls, at least some of the plurality of polymer walls extending between the substrates and defining a plurality of compartments therein; and removing the photomask. In some embodiments, the light modulating device further comprises a voltage source in electrical communication with the first electrically conductive element and the second electrically conductive element.

These and other embodiments are described in greater detail below. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section of the light modulating device depicting the schematics of the light modulating device in accordance with the concepts of the current disclosure.

FIG. 2 is an image of the light modulating device embodiment of Comparative Example

1 as viewed through crossed polarizers. Crossed arrows indicate that polarizers were crossed. The length of the scale bar represents 100 pm.

FIG. 3 is an image of the light modulating device embodiment of Comparative Example

2 as viewed through crossed polarizers. Crossed arrows indicate that polarizers were crossed. The length of the scale bar represents 100 pm.

FIG. 4A is an image of the light modulating device embodiment of Example 1A (PTZ 0.01 wt%) as viewed through crossed polarizers. Crossed arrows indicate that polarizers were crossed. The length of the scale bar represents 100 pm.

FIG. 4B is an image of the light modulating device embodiment of Example IB (PTZ 0.1 wt%) as viewed through crossed polarizers. Crossed arrows indicate that polarizers were crossed. The length of the scale bar represents 100 pm. FIG. 4C is an image of the light modulating device embodiment of Example 1C (PTZ 1.0 wt%)as viewed through crossed polarizers. Crossed arrows indicate that polarizers were crossed. The length of the scale bar represents 100 pm.

FIG. 5Ais an image of the light modulating device embodiment of Example 2A (Q1301 1.0 wt%) as viewed through crossed polarizers. Crossed arrows indicate that polarizers were crossed. The length of the scale bar represents 100 pm.

FIG. 5B is an image of the light modulating device embodiment of Example 2B (PTZ 1.0 wt%)as viewed through crossed polarizers. Crossed arrows indicate that polarizers were crossed. The length of the scale bar represents 100 pm. FIG. 6Ais an image of the light modulating device embodiment of Example 3A (OB+ 0.5 wt%) as viewed through crossed polarizers. Crossed arrows indicate that polarizers were crossed. The length of the scale bar represents 100 pm.

FIG. 6B is an image of the light modulating device embodiment of Example 3B (UV-790 0.5 wt%) as viewed through crossed polarizers. Crossed arrows indicate that polarizers were crossed. The length of the scale bar represents 100 pm.

FIG. 7Ais an image of the light modulating device embodiment of Example 3B as viewed through crossed polarizers. Crossed arrows indicate that polarizers were crossed. The length of the scale bar represents 100 pm. FIG. 7B is an image of the light modulating device embodiment of Example 3B as viewed through crossed polarizers. Crossed arrows indicate that polarizers were crossed. The length of the scale bar represents 100 pm.

FIG. 8 is an image of the light modulating device embodiment of Example 4 as viewed through crossed polarizers. Crossed arrows indicate that polarizers were crossed. The length of the scale bar represents 100 pm.

DETAILED DESCRIPTION

The present disclosure relates to improved light modulating devices that have polymer wall compartmentalized light modulating formulations and in-situ methods for making the same. In some embodiments of the current disclosure, a light modulating device may be used in window type applications for energy efficiency and privacy. The light modulating devices of the present disclosure may be switched between an opaque light scattering state to a transparent state by the application of an electric field. The present disclosure describes a light shutter, when in the opaque light scattering state requires no electric field. The present disclosure describes a light shutter that operates at a low driving voltage. Therefore, the light modulating device of the present disclosure may be energy-saving. The present disclosure describes a light modulating device that may provide improved in-situ formation of discrete polymer walls. Therefore, the light modulating device described herein may be made by continuous roll-to-roll methods. Use of the term "may" or "may be" should be construed as shorthand for "is" or "is not" or, alternatively, "does" or "does not" or "will" or "will not," etc. For example, the statement "the liquid crystal composition may comprise a photoinitiator" should be interpreted as, for example, "In some embodiments, the liquid crystal composition comprises a photoinitiator," or "In some embodiments, the liquid crystal composition does not comprise a photoinitiator," or "In some embodiments, the liquid crystal composition will comprise a photoinitiator," or "In some embodiments, the liquid crystal composition will not comprise a photoinitiator," Etc.

The term "transparent" as used herein, includes structures that do not absorb, reflect, or scatter a significant amount of visible light radiation; rather, a transparent substrate allows most visible light radiation to pass through. For example, a structure is transparent if the features of an object can be seen through the structure.

The term "diffusing reactive polymer subunits" as used herein, may include the original or unpolymerized monomers, e.g., the precursor monomer units prior to polymerization, and the created polymer chain comprising the reactive monomer subunits after exposure to polymerizing radiation, e.g., the polymer walls.

The terms "light modulating formulation," "precursor polymer composition," "precursor formulation," "precursor composition," "polymerizable liquid crystal composition," or "polymerizable composition" may each include any mixture comprising a pre-polymerized monomer, a polymerizable mixture, a mixture containing a monomer and a liquid crystal compound, in addition to additives comprising polymerization inhibitors, UV blockers, photoinitiators, chiral dopants, microsphere spacer beads, or a combination thereof.

The term "about" as used herein, includes any numerical value that may vary without changing the basic function of that value. When used with a range, "about" also discloses the range defined by the absolute values of the two endpoints. The term "about" may refer to plus or minus 10% of the indicated number.

Some embodiments, as shown in FIG. 1, include a light modulating device, such as device 10. In some examples, the light modulating device may comprise a first transparent electrically conductive element 12; a second transparent electrically conductive element 14; a plurality of polymer walls 18 bonded respectively to and between the first and second transparent electrically conductive elements, wherein the polymer walls define plural compartments, such as compartments 20, therebetween. The respective electrically conductive elements may comprise respective substrates 22A and 22B and a respective transparent electrically conductive layers 24A and 24B. A cell gap G may space apart the first and second transparent electrically conductive elements and contain a diffusing reactive monomer and a liquid crystal compound which may be polymerized in situ to afford compartments of mostly liquid crystal compound contained within polymer walls. The width of the polymer wall line may have a dimension L and the dimension of the defined compartment may be S. Electrical leads, 26A or 26B, may be attached to the electrically conductive layers. An external voltage source (not shown) may be connected to the electrical leads to switch the light modulating device from an opaque state to a transparent state. The voltage source may be an AC voltage source. In some cases, the voltage source may be an AC-DC inverter and a battery. In some embodiments, the voltage source may be a DC battery, such as thin cell.

In some embodiments, a method for making a light modulating device includes growing of a polymer wall by exposing an area to a curing radiation, and double-sided additive polymerization of the diffusing reactive monomer subunits within the area exposed to a curing radiation. Double-sided additive polymerization comprises polymerizable monomers diffusing to the site of curing radiation from locations on either side of the polymer wall being created. After in-situ polymerization, the polymer wall may comprise at least 90 wt% of the precursor unpolymerized diffusing reactive monomer subunits, and less than 10 wt% of the liquid crystal compound, said reactive diffusing monomer subunits having a diffusion coefficient determining, characterizing, and/or enabling the diffusion of the reactive monomer from a first position within the defined compartment along a path half the length S of the defined compartment to a position defining a portion of the polymer wall within a given curing time. In some embodiments, after formation of the polymer walls, the liquid crystal composition within the defined compartments may comprise less than 10 wt% of said reactive monomer and at least 90 wt% of said liquid crystal compound, the transparent light modulating device has a visual transparency of at least 75%. In some embodiments, the transparent light modulating device may comprise a first electrically conductive element and/or a second electrically conductive element. In some embodiments, the first and/or second substrates may be transparent and/or selectively transparent. In some embodiments, the transparent electrical electrodes may be, for example, non-conductive substrates, 22A or 22B. In some embodiments the transparent electrically conductive elements may comprise electron conduction layers 24A or 24A, wherein the electron conduction layers are disposed upon or layered upon the non-conductive substrates. In some embodiments, the electrically conductive element may comprise a conductive material. In some embodiments, the conductive material may comprise conductive polymers. In some embodiments, the conductive polymers may comprise poly(3,4-ethylenedioxythiophene) (PEDOT), PEDOT: polystyrene sulfonate) (PSS), or a combination thereof.

In some embodiments, each transparent electrically conductive element may comprise an electrically conducting layer, where the layer is in physical contact with the substrate. In some embodiments, the electron conductive layer is placed in direct physical communication with the substrate, such as a layer on top of the substrate. In other embodiments, the electrically conductive layer may be deposited upon the substrate (e.g. ITO glass) or sandwiched in between two bases to form a single conductive substrate. In some embodiments, where there is an electrically conductive layer present, the substrate may comprise a non-conductive material. In some embodiments, the non-conductive material may comprise glass, a polymer, or a combination thereof. In some embodiments, the substrate polymer may comprise polyvinyl alcohol (PVA), polycarbonate (PC), acrylics including but not limited to Poly(methyl methacrylate) (PMMA), polystyrene, allyl diglycol carbonate (e.g. CR-39), polyesters, polyetherimide (PEI) (e.g. Ultem^®), Cyclo Olefin polymers (e.g. Zeonex^®), triacetylcellulose (TAC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or combinations thereof. In some embodiments, the substrate may comprise polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or a combination thereof. In some embodiments, the electrically conductive layer may comprise a transparent conductive oxide, conductive polymer, metal grids, carbon nanotubes (CNT), graphene, or a combination thereof. In some embodiments, the transparent conductive oxide may comprise a metal oxide. In some embodiments, the metal oxide may comprise iridium tin oxide (IrTO), indium tin oxide (ITO), fluorine doped tin oxide (FTO), doped zinc oxide, or combinations thereof. In some embodiments, the metal oxide may comprise indium tin oxide incorporated onto the base, e.g. ITO glass, ITO PET, or ITO PEN.

In some embodiments, a liquid crystal compound and a diffusing reactive monomer precursor composition is described, wherein the precursor composition is disposed between the transparent electrically conductive elements prior to exposure to polymerizing or curing radiation. In some embodiments, the precursor composition may comprise 10 wt% to about 50 wt% diffusing reactive monomers (e.g. about 10-20%, about 20-30%, about 30-40%, about 40-50%, about 10-30%, about 30-50%, or about 22-66%). In some embodiments, the precursor composition may comprise 90 wt% to about 50 wt% light modulating compound, e.g., a liquid crystal compound. In some embodiments, the precursor composition may comprise 0.01 wt% to about 5.0 wt%, e.g., about 0.5 wt%, of a UV blocker compound. In some embodiments, the precursor composition may comprise 0.01 wt% to about 5.0 wt% , e.g., about 0.5 wt% or about 1.0 wt% of a polymerization inhibitor compound. In some embodiments, the precursor composition may comprise 0.01 wt% to about 5.0 wt%, e.g., about 0.5 wt% of a photoinitiator compound. In some embodiments, the precursor composition may comprise 0.01 wt% to about 5.0 wt%, e.g., about 0.5 wt% of microsphere spacer beads. In some embodiments, the precursor composition may comprise 1 wt% to about 10 wt% of a chiral dopant.

In some embodiments, a plurality of polymer walls may be bonded to and/or between the first and second transparent electrically conductive elements. In some embodiments, the selectively polymerized polymer wall may have a composition of at least 90 wt% now polymerized (or formerly unpolymerized) reactive polymer subunits. In some embodiments, the selectively polymerized polymer wall has a composition of less than 10 wt% of trapped liquid crystal compound. In some embodiments, the less than 10 wt% liquid crystal compound may be in the form of droplets containing liquid crystal compound present in polymer walls. It is desired that the droplets have a diameter no larger than about 0.4 pm. In some embodiments, droplets having a diameter of 0.4 pm may contribute to Mie scattering. It is believed that reducing the amount of liquid crystal droplets retained within the polymer walls, the undesired Mie-type light scattering may be reduced and the resulting layer of material may be more transparent and/or less hazy. The plurality of compartments may, in some embodiments, form a pattern of two dimensional repeating polygons, such as a triangle, square, rectangle, pentagon, hexagon, diamond, etc., wherein the sides of the polygons are formed by the polymer walls. For the purposes of this disclosure, the width of a polygon is the length of the longest line from one side of the polygon to another side of the polygon through the center of the polygon. In some embodiments, the dimension S of the geometric feature may be the width or side dimension of the repeating geometric feature, e.g., squares or hexagons, which are liquid crystal rich, within which liquid crystals may freely flow. It is believed that the repeating geometrically shaped compartments may reduce the internal undesired macroscopic flow of the light modulating compound, e.g., liquid crystal, within the cell gap. In some embodiments, the width or side dimension of the repeating geometric feature may be chosen between a minimum value - no smaller than cell gap size of the device (for example 10 pm) to ensure that optical properties of the light modulating device are not hindered. In some embodiments, the value of the width or side dimension of the repeating geometric feature may be chosen as less than a maximum value - no larger than capillary length lc=(y/(p-g))^1/2, where y is LC surface tension, p is LC density and g is gravitational acceleration on Earth. For example, if y=35 mN/m, p=1000 kg/m³, and g=9.81 m/s², then l_c=1.89 mm, thus, 10 pm < S < 1890 pm.

In some embodiments, the width or side dimension of the repeating geometric feature of the defined compartment may be about 10-2000 pm, about 10-20 pm, about 20-30 pm, about 30-40 pm, about 40-50 pm, about 50-60 pm, about 60-70 pm, about 70-80 pm, about 80-90 pm, about 90-100 pm, about 100-120 pm, about 120-140 pm, about 140-160 pm, about 160-180 pm, about 180-200 pm, about 200-220 pm, about 220-240 pm, about 240-260 pm, about 260-280 pm, about 280-300 pm, about 100-200 pm, about 200-300 pm, about 300-400 pm, about 400-500 pm, about 500-600 pm, about 600-700 pm, about 700-800 pm, about 800-900 pm, about 900-1000 pm, about 1000-1250 pm, about 1250-1500 pm, about 1500- 2000 pm, about 100-150 pm, about 150-200 pm, about 200-250 pm, about 250-300 pm, about 300-350 pm, about 350-400 pm, about 100-300 pm, about 200-400 pm, about 100-400 pm, or about any range bounded by any of these values.

In some embodiments, the polymer walls comprise less than a negligible quantity of trapped liquid crystal composition, e.g., less than about 10 wt% of the liquid crystal compound. In some examples, the quantity of trapped liquid crystal composition is less than about 9 wt%, less than about 8 wt%, less than about 7 wt%, less than about 6 wt%, less than about 5 wt%, less than about 4 wt%, less than about 3 wt%, less than about 2 wt%, or less than about 1 wt%, of the liquid crystal compound. In some embodiments, the polymer walls comprise a substantial majority of the cured reactive monomer, greater than about 90 wt% of the original monomer precursor or cured monomer precursor. In some cases, the polymer walls comprise greater than about 91 wt%, greater than about 92 wt%, greater than about 93 wt%, greater than about 94 wt%, greater than about 95 wt%, greater than about 96 wt%, greater than about 97 wt%, greater than about 98 wt%, or greater than about 99 wt%, of the original monomer precursor or cured monomer precursor. In some embodiments, the polymer walls may comprise less than 10 wt% liquid crystal droplets of less than or equal to about 0.4 pm in diameter. Suitable means to determine whether or not the polymer walls comprise a substantial majority of the cured reactive monomer, greater than 90 wt% of the original monomer precursor, or cured monomer precursor, may be by microscopic examination of the light modulating device embodiment. If microscopic examination reveals the absence of droplets in the polymer walls then it is believed that droplets of size of about 0.4 pm or greater are not present. As noted above, it is believed that minimizing the amount of liquid crystal composition within the polymer walls may reduce undesired light scattering (Mie scattering) by trapped liquid crystal droplets within said polymer walls.

In some embodiments, the polymer wall has spatial dimensions facilitating the selective polymerization of the reactive monomer. In some embodiments, the polymer wall has a width L between 1 micron to about 100 pm (microns or micrometers) for a diffusion time between 1 and 30 minutes, e.g., about 7-10 minutes. In some embodiments, the polymer compartment has a width or side dimension of the repeating geometric feature of between 10 microns to about 2000 microns. In some embodiments, the reactive monomers diffuse more rapidly than the liquid crystal compound. It is believed that this may allow the monomer to be a significantly large portion of the polymerization that forms the polymer walls. For example, size of the compartment may be chosen so that most of the reactive monomer, but only a small fraction of the liquid crystal compound, has sufficient time to diffuse to the wall that is being formed by photopolymerization while the area is being exposed to ultraviolet light. This may allow selective curing or polymerization of the reactive polymers characterized by the desired aforedescribed wt% levels of reactive (or unreacted or unpolymerized) monomers. It is believed that the described dimensions and diffusion coefficient of reactive monomer may reduce or minimize the amount of liquid crystal compound remaining in areas selected as polymer walls.

In some embodiments, the spatial dimensions of the polymer walls include considerations relative to the visual perception of the device appearance. The width of the polymer walls must be small enough to be invisible to the human eye. The resolution of human eye is limited by diffraction limit expressed by Raleigh criterion as 0=1.22-A/D where Q is angular resolution, l is wavelength of light, for example 550 nm, and D is a typical pupil diameter at day light, therefore q=2.2·10⁴ radians. The smallest resolvable feature at comfortable viewing distance d=25 cm is therefore: L=2-d-tan(0/2), thus L=55 pm. Preferably, the width of the polymer wall is even smaller, for example 30 pm, or even smaller such as equal to spacer diameter of about 10 pm to minimize haze in the transparent state of the device. In some embodiments, the width of the polymer wall is about 1-100 pm, about 1-5 pm, about 5-10 pm, about 10-15 pm, about 15-20 pm, about 20-25 pm, about 25-30 pm, about 30-35 pm, about 35-40 pm, about 40-45 pm, about 45-50 pm, about 50-55 pm, about 55-60 pm, about 60-80 pm, about 80-100 pm, about 10-20 pm, about 15-25 pm, about 20-30 pm, about 25-35 pm, about 30-40 pm, about 35-45 pm, about 40-50 pm, about 45-55 pm, about 10-55 pm, about 10 pm, about 15 pm, about 20 pm, about 25 pm, about 30 pm, about 35 pm, about 40 pm, about 45 pm, about 50 pm, about 55 pm, or about any width in a range bounded by any of these values.

In some embodiments, the diffusing reactive monomer subunit has a diffusion coefficient determining the diffusion distance of the reactive monomer along a path greater than one half the length of the plural compartment within a desired polymerization time.

In some embodiments, the desired polymerization time may be dictated by the selected manufacturing process, e.g., in a manner similar to the manufacturing process as described in United States Patent No. 10,338,431. For example, the transparent light modulating device material may be produced in the following manner by a roll-to-roll process. In the roll-to-roll process, a first and a second flexible electrically conductive element may be fed from their respective rolls and then a polymerizable liquid crystal composition may be inserted between the electrically conductive elements. The resulting construct may be irradiated (cured) in a predetermined pattern with ultraviolet light, visible light, or other electromagnetic radiation. In some embodiments, the curing may occur at less than the clearing temperature point of liquid crystal compound, e.g., QYPDLC-8, the clearing temperature point was about 73 °C. In some embodiments, the curing may be conducted below the thermal breakdown of the organic compounds of the light modulating device, e.g., 260 °C, the melting temperature of the PET substrate. In some embodiments this may processed at room temperature. It is believed that high thermal environments, e.g., above 200 °C, could adversely affect the materials used in the processing of the light modulating materials/layers/devices. Thus, the flexible light modulating device may be produced.

In some embodiments, in orderto satisfy the spatial dimensions desired, the diffusing reactive monomer subunit may have a desired diffusion coefficient. In some embodiments, the reactive monomer has a diffusion coefficient sufficient to enable the reactive monomer to diffuse from a first position within the defined compartment location to a second position at the desired polymer wall position. This diffusion must be sufficiently timely to enable a substantial portion of the reactive monomer subunits, e.g., at least about 90 wt%, to be consumed, e.g., polymerized, within the desired polymerization time frame, as suggested above as between 1 to 30 minutes, e.g., 7 to 10 minutes. In some embodiments, at least one half the distance between the polymer walls S, may be the distance the reactive monomer may travel from within the purported compartment spatial location to the polymerizing wall location may be less than or equal to sufficient the diffusion length of the reactive monomer for the desired polymerization or curing time. In one embodiment, the diffusion length is determined by taking the square root of the mean squared displacement: 1= ((c^L2 ))^1/2. The mean squared displacement may be calculated using the following relation:

(x² )=2-d-D-tcure where d is the number of dimensions, for example d=2 in the case of a device with flat geometry, and D is the diffusion coefficient of the reactive monomer in light modulating precursor formulation. In some embodiments, the diffusion coefficient of the reactive monomer satisfies dimensional and temporal requirements that may be predicted by using the Stokes-Einstein relation:

D=(k_bT)/(6n-p-rvr), where k_b is the Boltzmann's constant, T is the temperature, p is the density of the formulation, h is the kinematic viscosity of the formulation and r is the hydrodynamic radius of the reactive monomer in the formulation. For example, an exemplary reactive monomer having the diffusion constant sufficient to traverse dimensions as set forth with a polymer wall having a width between about 1 micron to about 100 microns and a lateral spacing of between about 10 microns to about 2000 microns within a curing period of ten minutes includes 2- phenoxyethyl acrylate. In some embodiments the reactive monomer subunit may comprise acryloyl morpholine, 2-phenoxyethyl acrylate, acrylic acid, ethylene glycol diacrylate and/or combinations thereof.

In some embodiments, the intensity of the polymerizing radiation may be between 0.1 mW/cm² to about 20 mW/cm², e.g., about 0.1-0.5 mW/cm², about 0.5-1 mW/cm², about 1-2 mW/cm², about 2-3 mW/cm², about 3-4 mW/cm², about 4-5 mW/cm², about 5-6 mW/cm², about 6-7 mW/cm², about 7-8 mW/cm², about 8-9 mW/cm², about 9-10 mW/cm², about 10-15 mW/cm², about 15-20 mW/cm², about 0.5 mW/cm², or about any range bounded by any of these values. In some embodiments, the length of exposure time may be between 1 minutes to about 30 minutes, e.g., when the curing intensity is about 0.5 mW/cm², the polymerization starts and completes within about 3 minutes. In some embodiments, the length of exposure time may be between about 1-5 minutes, about 5-10 minutes, about 10- 15 minutes, about 15-20 minutes, about 20-25 minutes, about 25-30 minutes, or any range bounded by any of these time periods. Curing kinetics may be evaluated and tuned by employing measurement techniques, e.g., photo-differential scanning calorimetry and/or by Fourier transform infrared spectroscopy equipped with a curing source, e.g., ultraviolet or visible light. A suitable method includes use of a Thermo Scientific Nicolet 6700 instrument with a UV light emitting diode lamp.

In some embodiments, the light modulating device may comprise a light modulating compound in the light modulating formulation that modulates light (scatters/absorbs/reflects, changes phase, etc.) upon the application of an external stimuli, for example causative radiation, thermal, ultraviolet (UV), visible light, electric field, and/or magnetic fields.

In some embodiments, the light modulating formulation of the light modulating device may comprise a polymerization inhibitor agent that may cause conversion delay of reactive monomer polymerization. In some embodiments, the reaction inhibitor may be phenothiazine, N-nitroso-N-phenylhydroxylamine aluminum salt, or a mixture thereof. It is believed that upon UV irradiation of reactive monomer containing formulation, the photo initiator molecules break down into radicals. These radicals initiate reactive monomer polymerization, but only after the polymerization inhibitor molecules are substantially consumed. Typically, formulations may contain dissolved oxygen, which may act as a reaction inhibitor. Therefore, a conversion delay is typically observed. An alternative description is that, due to establishing of concentration gradient, there is a higher concentration of the inhibitor at the interface between the exposed curing radiation position and the non-exposed radiation position. Inhibitor concentration is above a threshold minimizing polymerization/conversion at the boundary and conversion/polymerization proceeds at the center or median position in the exposed radiation area, where the concentration is lower as it had been consumed. This may help to confine polymerization, and the resultant wall formation, to the area that is being exposed to the ultraviolet radiation. This phenomenon may be made even more pronounced by adding additional inhibitor compounds and/or agents. It is believed that this procedure contributes to the double-sided additive polymerization formation of the polymer wall from the center of the exposed radiation area outwards towards the boundary of the exposed and un-exposed photomasked areas. In some embodiments, the polymerization inhibitor additives may comprise about 0.01 wt% to about 5.0 wt%, about 0.01-0.05 wt%, about 0.05-0.1 wt%, about 0.1-0.5 wt%, about 0.5-1 wt%, about 1-2 wt%, about 2-3 wt%, about 3-4 wt%, about 4-5 wt%, about 0.01 wt%, about 0.05 wt%, about 0.1 wt%, about 0.5 wt%, about 0.008-0.012 wt%, about 0.8-1.2 wt%, about 0.08- 0.12 wt%, about 0.4-0.6 wt%, about 1 wt%, or about any wt% in a range bounded by any of these values, of the precursor mixture. In some embodiments, suitable inhibitor additives may be PTZ (phenothiazine, CAS: 92-84-2), Q-1301 (N-nitroso-N-phenylhydroxylamine aluminum salt, CAS: 15305-07-4), HQ (hydroquinone, CAS: 123-31-9), TBC (tert-butyl catechol, CAS: 98-29-3), MEHQ (ME hydroquinone, CAS: 26570-48-9), or any combination thereof. In some embodiments, the formulation may comprise PTZ. It is believed that PTZ is suitable because it has a relatively lower molecular weight (less than 250g/mol) and therefore may have a higher molecular mobility. In some embodiments, the light modulating device/formulation may comprise a UV blocker agent. For the purposes of the present disclosure, the terms "UV blocker" and "UV absorber" are deemed to be equivalent and interchangeable. In some embodiments, the UV blocker agent may be a UV absorber such as OB+ (Cas: 7128-64-5), UV-790 (Qidong Jinmei Chemical Co.), or a combination thereof. It is believed that the morphology of polymerizing polymer wall is relatively rough, due to Raleigh-Taylor instabilities, enabling scattering of the polymerizing radiation outside of the desired or intended area of exposure. It is believed that incorporation of a UV blocker agent reduces the polymerization or conversion effects due to scattered UV radiation outside of the desired (un-photomasked) area. In some embodiments, the content of UV blocker agent may be about 0.01 wt% to about 5.0 wt%, about 0.01-0.05 wt%, about 0.05-0.1 wt%, about 0.1-0.5 wt%, about 0.5-1 wt%, about 1-2 wt%, about 2-3 wt%, about 3-4 wt%, about 4-5 wt%, about 0.4-0.6%, about 0.01 wt%, about 0.05 wt%, about 0.1 wt%, about 0.5 wt%, about 1 wt%, or about any wt% in a range bounded by any of these values, of the mixture.

In some embodiments, a residual composition may be contained, remain, retained and/ or encompassed within the compartments defined by the polymer walls. In some embodiments, the residual composition may comprise the unpolymerized/unconverted precursor composition remaining after the exposure to curing radiation. In some embodiments, the residual composition may comprise a liquid crystal formulation. In some embodiments, the liquid crystal formulation may be disposed within the plurality of compartments defined by the polymer walls. In some embodiments, the liquid crystal composition disposed within the compartments defined by the polymer walls comprise less than a negligible quantity of reactive monomer remaining therein, e.g., greater than 90 wt% liquid crystal compound and less than 10 wt% of reactive monomer. In some embodiments, the material contained or disposed within the compartments comprise a substantial majority of the liquid crystal compound, greater than 90 wt% liquid crystal compound.

In some embodiments, the liquid crystal formulation may include a nematic liquid crystal material. In some embodiments, the liquid crystal formulation may include a cholesteric liquid crystal material. In some embodiments, the liquid crystal formulations may include QYPDLC-8, MLC2132, or a combination thereof. In some embodiments, the liquid crystal formulation or liquid crystal precursor may contain about 50-95%, about 50-70%, about 70-95%, about 50-60%, about 60-70%, about 70-80%, about 80-90%, or about 75% of the liquid crystal material or compound.

In some embodiments, the liquid crystal composition may comprise a photoinitiator. In some embodiments, the photoinitiator may comprise a UV irradiation photoinitiator. In some embodiments, the photoinitiator may also comprise a co-initiator. In some embodiments, the photoinitiator may comprise an a-alkoxydeoxybenzoin, a,a- dialkyloxydeoxybenzoin, a,a-dialkoxyacetophenone, a,a-hydroxyalkylphenone, O-acyl a- oximinoketone, dibenzoyl disulphide, S-phenyl thiobenzoate, acylphosphine oxide, dibenzoylmethane, phenylazo-4-diphenylsulphone, 4-morpholino-a- dialkylaminoacetophenone and combinations thereof. In some embodiments, the photoinitiator may comprise ethyl (2,4,6-trimethylbenzoyl) phenyl phosphinate (TPO-L), Irgacure^® 184, Irgacure^® 369, Irgacure^® 500, Irgacure^® 651, Irgacure^® 907, Irgacure^® 1117, Irgacure^® 1700, 4,4'-bis(N,N-dimethylamino)benzophenone (Michlers ketone), (1- hydroxycyclohexyl) phenyl ketone, 2,2-diethoxyacetophenone (DEAP), benzoin, benzyl, benzophenone, or combinations thereof. In some embodiments, the photoinitiator may comprise a blue-green and/or red sensitive photoinitiator. In some embodiments, the blue- green and/or red photoinitiator may comprise Irgacure^® 784, dye rose bengal ester, rose Bengal sodium salt, campharphinone, methylene blue and the like. In some embodiments, co-initiators may comprise N-phenylglycine, triethylamine, thiethanolamine and combinations thereof. It is believed that co-initiators may control the curing rate of the original pre-polymer such that material properties may be manipulated. In some embodiments, the photoinitiator may comprise an ionic photoinitiator. In some embodiments, the ionic photoinitiator may comprise a benzophenone, camphorquinone, fluorenone, xanthone, thioxanthone, benzyls, a-ketocoumarin, anthraquinone, terephthalophenone, and combinations thereof. In some embodiments, the photoinitiator is a Type I photoinitiator. In some embodiments, the photoinitiator may comprise TPO-L. In some embodiments, the photoinitiator may be about 0.01 wt% to about 5.0 wt%, about 0.01- 0.05 wt%, about 0.05-0.1 wt%, about 0.1-0.5 wt%, about 0.5-1 wt%, about 1-2 wt%, about 2- 3 wt%, about 3-4 wt%, about 4-5 wt%, about 0.01 wt%, about 0.4-0.6%, about 0.8-1.2%, about 0.05 wt%, about 0.1 wt%, about 0.5 wt%, about 1 wt%, or about any wt% in a range bounded by any of these values, of the precursor mixture. In some embodiments, wherein the light modulating device may comprise a light modulating compound and further comprise a chiral dopant, the light modulating layer may effect a change in transparency (or opacity) by reduction of haze to below 10% upon the application of less than 25 volts to a device with for a 10 micron cell gap (less than 2.5 volts per micron). In some embodiments, the light modulating device comprising a chiral dopant may be suitable for smart window applications. In some embodiments, wherein the light modulating device may comprise a light modulating compound, comprising a chiral dopant, the light modulating layer may effect a change in transparency to below 10% upon the application of less than 5 volts for a 10 micron gap (less than 0.5 volts per micron). In some embodiments, the chiral dopant may comprise about 1 wt% to about 10 wt%, about 1-2 wt%, about 2-3 wt%, about 3-4 wt%, about 4-5 wt%, about 5-6 wt%, about 6-7 wt%, about 7-8 wt%, about 8-9 wt%, 9-10 wt%, about 6-8 wt%, about 6 wt%, or about any wt% in a range bounded by any of these values, of the precursor mixture.

In some embodiments, the liquid crystal composition may comprise microsphere spacer beads. In some embodiments, the microsphere spacer beads may comprise Nanomicro HT100 spacer beads. In some examples, the spacer beads may be about 5-20 pm, about 5-6 pm, about 6-7 pm, about 7-8 pm, about 8-9 pm, about 9-10 pm, about 10-11 pm, about 11-12 pm, about 12-13 pm, about 13-14 pm, about 14-15 pm, about 15-16 pm, about 16-17 pm, about 17-18 pm, about 18-19 pm, about 19-20 pm, about 8-12 pm, about 10 pm, or about any size in a range bounded by any of these ranges. In some embodiments, the microsphere spacer beads may be present in about 0.01 wt% to about 5.0 wt%, about 0.01- 0.05 wt%, about 0.05-0.1 wt%, about 0.1-0.5 wt%, about 0.5-1 wt%, about 1-2 wt%, about 2- 3 wt%, about 3-4 wt%, about 4-5 wt%, about 0.01 wt%, about 0.05 wt%, about 0.1 wt%, about 0.5 wt%, about 1 wt%, or about any wt% in a range bounded by any of these values, of the precursor mixture.

Some embodiments include a method for making a transparent light modulating device. In some embodiments, the method may comprise providing a pair of substrates; disposing a polymer precursor composition between the substrates, the polymer composition precursor comprising a diffusing reactive monomer substrate and a liquid crystal compound; growing a polymer wall structure between the substrates by selectively curing the reactive monomer, wherein the polymer wall grows outward from a first medially defined start position, i.e., the center of where the wall is to be formed, to a second laterally displaced subsequent position within an area exposed to a curing radiation; wherein the polymer wall consists of at least 90 wt% from reactive monomer and less than 10 wt% of the liquid crystal compound therein; wherein the polymer walls define a plurality of compartments therein; wherein the residual composition retained within the plurality of compartments comprise less than 10 wt% of diffusive reactive monomer and at least 90 wt% of the liquid crystal compound.

In some embodiments, the method for creating the polymer wall structure comprises: placing a photomask upon one of the substrates, the photomask comprising transparent lines (apertures) of width L and non-transparent areas having a dimension S (see FIG. 1); applying photocuring radiation through the photomask apertures upon the liquid crystal and polymer precursor composition for a period of time and intensity to cure the reactive monomer and form a plurality of polymer walls, at least some of the plurality of polymer walls extending between the substrates and defining a plurality of compartments therein; and/or removing the photomask. In some embodiments, the photomask defines dimensions of a polymerwall width of between 1 micron to about 100 microns. In some embodiments, the photomask defines dimensions of a polymer wall which defines a compartment having a lateral spacing of between 10 microns to about 2000 microns. In some embodiments, the sufficient time is defined by the formula:

(x² )=2‘d‘D‘tcure, where d is the number of dimensions, for example d=2 in the case of a device with flat geometry, D is the diffusion coefficient of the diffusing reactive monomer subunit in the precursor polymer formulation, the residual composition and / or liquid crystal compound and t_cur_e is the allowed curing time. The mean squared displacement must be equal or larger than S/2, where S is the distance between the polymer walls.

In some embodiments, the pair of opposing transparent electrodes are individually disposed upon a substantially transparent substrate. The substrate is not particularly limiting, and one skilled in the art of light shutters would be able to determine an appropriate material for the substantially transparent substrates. Some non-limiting examples include glass and polymerfilms. Typical polymerfilms include films made of polyolefin, polyester, polyethylene terephthalate, polyvinyl chloride, polyvinyl fluoride, polyvinylidene difluoride, polyvinyl butyral, polyacrylate, polycarbonate, polyurethane, etc., and combinations thereof.

The light modulation devices described herein are useful in methods for controlling the amount of light and/or heat passing through a light modulating device. The light modulation devices described herein may further be useful in efforts to provide privacy, reduce heat from ambient sunlight, and control harmful effects of ultraviolet light.

Hereinafter, exemplary embodiments and methods will be described in more detail.

EMBODIMENTS

Embodiment 1 A light modulating device comprising: a first transparent electrically conductive element; a second transparent electrically conductive element; a light modulating layer, said light modulating layer comprising diffusing reactive monomer subunits, a liquid crystal compound, a polymerization inhibitor compound, and a UV blocker compound, said light modulating layer disposed between the first and second transparent electrically conductive elements; a plurality of polymer walls bonded respectively to and between the first transparent electrically conductive element and the second transparent electrically conductive element, the polymer walls defining plural compartments therebetween, the polymer walls comprising at least 90 wt% of the diffusing reactive monomer subunits and less than 10 wt% of the liquid crystal compound, said reactive diffusing monomer subunits having a diffusion co-efficient determining the diffusion of the reactive monomer subunits from a position within the defined compartment along a path half the length of the defined compartment to a position defining a portion of the polymer wall within a given curing time; and a residual composition comprising at least 90 wt% of the liquid crystal compound and less than 10 wt% of the diffusing reactive monomer subunit, said residual composition contained within said defined compartments.

Embodiment 2 The light modulating device of embodiment 1, wherein the polymerization inhibitor compound is phenothiazine, N-Nitroso-N-phenylhydroxylamine Aluminum Salt, or mixtures thereof. Embodiment 3 The light modulating device of embodiment 1, wherein the UV- blocker compound is 2,5-Bis(5-tert-butyl-benzoxazol-2-yl)thiophene, UV-790 and mixtures thereof.

Embodiment 4 The light modulating device of embodiment 1, wherein, the liquid crystal composition within the defined compartments may comprise less than 10 wt% of said reactive monomer and at least 90 wt% of said liquid crystal compound.

Embodiment 5 The light modulating device of embodiment 1, wherein the diffusing reactive monomer has a diffusion coefficient determining the diffusion distance of the diffusing reactive monomer along a path greater than one half the length of the plural compartment within ten minutes of polymerization time.

Embodiment 6 The light modulating device of embodiment 1, wherein the polymer wall has a width L between 1 micron to about 100 microns for a diffusion time between 1 and 30.0 minutes.

Embodiment 7 The light modulating device of embodiment 1, wherein the polymer wall has a lateral spacing S of between 10 microns to about 2000 microns.

Embodiment 8 The light modulating device of embodiment 1, wherein the diffusing reactive monomer subunit may comprise acryloyl morpholine, 2-phenoxyethyl acrylate, acrylic acid, ethylene glycol diacrylate or combinations thereof.

Embodiment 9 A precursor polymer composition comprising:

10 wt% to 50 wt% diffusing reactive monomer subunits;

90 wt% to about 50 wt% liquid crystal compound;

0.01 wt% to 5.0 wt% polymerizing inhibitor compound;

0.01 wt% to 5.0 wt% ultraviolet inhibitor compound; and

0.01 wt% to about 5.0 wt% photoinitiator.

Embodiment 10 A method for making a light modulating device comprising: providing a pair of electrically conductive elements; disposing a polymer precursor composition between the electrically conductive elements, the polymer precursor composition comprising diffusing reactive monomer subunits, a liquid crystal compound, a polymerization inhibitor compound and a ultraviolet light blocker compound; growing a polymer wall structure between the electrically conductive elements by selectively curing the reactive monomer subunits, said polymer wall growing with a minimal entrapment of liquid crystal compound therein, said polymer wall made of at least 90 wt% from reactive monomer subunits and less than 10 wt% of the liquid crystal compound therein, said polymer walls defining a plurality of compartments therein; and a residual composition within said plurality of compartments, said residual composition comprising a less than 10 wt% of diffusing reactive monomer subunits and at least 90 wt% of the liquid crystal compound.

Embodiment 11 The method of embodiment 10, wherein the growing of a polymer wall comprises exposing an area to a curing radiation, and double sided additive polymerization of the diffusing reactive monomer subunits within the area exposed to a curing radiation.

Embodiment 12 The method of embodiment 10, wherein the growing a polymer wall may comprise placing a photomask, having defined apertures therein, upon one of the substrates, the photomask having a polymer wall width L and a compartment spacing S; applying a photocuring radiation through the photomask apertures upon the polymer precursor composition for a period of time and intensity to cure the reactive monomers and form a plurality of polymer walls, at least some of the plurality of polymer walls extending between the substrates and defining a plurality of compartments therein; and removing the photomask.

Embodiment 13 The method of embodiment 12, wherein the photomask defines dimensions of a polymer wall width of between 1 micron to about 100 microns.

Embodiment 14 The method of embodiment 12, the photomask defines dimensions of a polymer wall which defines a compartment having a lateral spacing S of between 10 microns to about 2000 microns.

Embodiment 15 The method of embodiment 11, the sufficient curing time is determined by the formula :

(x² )=2 d D tcure, where d is 2, D is the diffusing reactive monomer subunits diffusion coefficient in the liquid crystal and polymer precursor formulation and t_CUre is the allowed curing time.

Embodiment 16 The method of embodiment 15, wherein the square root of mean squared displacement is equal or larger than S/2, where S is the distance between the polymer walls. EXAMPLES

It has been discovered that embodiments of the light modulating device described herein have improved performance as compared to other forms of light modulating devices. These benefits are further demonstrated by the following examples, which are intended to be illustrative of the disclosure only but are not intended to limit the scope or underlying principles in any way.

Creation of Polymerizable Liquid Crystal Compositions:

For Ex-3A, a mixture of 75 wt% of nematic liquid crystal material QYPDLC-8 (Qingdao QY Liquid Crystal Co. Ltd.), 23.0 wt% 2-phenoxyethyl acrylate (ethylene glycol phenyl ether acrylate, PEA) (Millipore Sigma , St. Louis, MO, USA), 0.5 wt% PTZ, and 0.5 wt% (OB+), and 0.5 wt% photo-initiator diphenyl (2,4,6-trimethylbenzoyl)phosphine oxide (TPO-L (Ciba Specialty Chemicals, Inc., Basel, Switzerland) was mixed in a 100 mL glass flask. The syrup was heated to just above the clearing point of the liquid crystal and mixed using a vortex mixer to form a homogeneous mixture. The process was repeated forthe additional compositions synthesized with the exception that the mass ratios of the constituents were varied as shown in Table 1.

TABLE 1

After mixing the aforementioned precursor formulations, an additional 1.0 wt% of the 10 pm microsphere spacer beads (Nanomicro HT100) were added. Fabrication of Light Modulating Device:

Two 3" long, 1.5"wide PET-ITO flexible substrates (Elecrysta C100-02RJC5B, Nitto Denko, Osaka, JP) were rinsed with acetone and blow-dried with compressed air. A droplet of a sample prepared as described above, e.g., formulation 3B, is then deposited on the surface of the conducting layer of the first substrate. The second substrate is placed on top of the droplet in contact with its conducting layer surface, a roller is then applied to spread the formulation between the substrates. Excess formulation extruding from the edges is removed, then the fabricated item is placed under a UV LED lamp (395 nm) for 15 minutes at an intensity of 0.5 mW/cm² at room temperature.

Afterwards, both substrates of the light modulating device with polymer walls may be electrically connected by soldering wires to the ITO terminals such that each conductive substrate are in electrical communication with a voltage source, where the communication is such that when the voltage source is applied an electric field will be generated across the device. The voltage source will provide the necessary voltage across the device to enable the reorientation of the liquid crystal molecules.

Characterization bv Polarizing Microscopy:

The optical characteristics of the transparent window panes were characterized by observing constructed samples on a polarizing optical microscope (AmScope PZ200TB Polarizing Trinocular microscope; United Scope LLC dba AmScope, Irvine CA, USA). Images of samples were recorded by equipping the POM with a camera (AmScope Digital Camera MU130 1.3 MP APTINA COLOE CMOS between crossed polarizers. The sample being assessed was placed on the POM stage. The polarizers were turned in a crossed configuration. An objective lens (for example, 4X, 10X, 40X) was chosen for a desired level of magnification , e.g., about 2500X's. Live observations were made on a computer screen using the digital camera. Position of the objective lens and microscope stage were adjusted until the image on the screen was in sharp focus. Photos and videos were captured using the bundled AmScope software (AmScope software was provided upon identification of the select camera, identified above, and operating system (Windows 10). Assessing the light allowed to pass through each fabricated light modulating element, see FIGs., 2, 3, 4A, 4B, 4C, 5A, 5B, 6A, 6B, 7 A, 7B, 8 for representative image of a device. The crossed arrows indicate that the polarizers were crossed. The length of the respective scale bars represents 100 pm. FIGs., 2, 3, 4A, 4B, 4C, 5A, 5B, and 6A, 8 exhibit trapped liquid crystal microdroplets within the polymer walls (18), as shown by the dot like structures within the walls. At least FIGs. 6A and 6B, 7 A, 7B, 8 exhibit liquid crystal rich compartments 20. FIGs. 6B, 7A, 7B exhibited an absence of trapped liquid crystal droplets within the polymer walls. FIGs. 6B, 7A, 7B and 8 also exhibited an absence of polymer aggregates within the liquid crystal containing compartments (20). Visual examination of the image, as shown in FIG. 7B (an increased magnification of FIG. 7A) indicates the almost total absence of droplets or spherical entities within the polymer walls and Schlieren type texture exhibited by the liquid crystal materials within compartments. It is believed that the image shows an absence of such entities, i.e., less than 10 wt% liquid crystal material within the polymer walls. This lack of entities exhibits a lack of micro-sized droplets of liquid crystal compound within the so constructed polymer walls (those micro sized droplets on the order of greater than about 0.4 microns).

In Example 4 (see FIG. 8), the liquid crystal formulation includes a chiral dopant component (R811, Merck), and in the absence of an electrical field, the sample is opaque. Application of an electrical field of about 2.4 volts per micron of the cell gap, the sample turns transparent.

While the present disclosure has been shown and described in connection with the embodiments, it will be apparent to those skilled in the art that modifications and variations may be made without departing from the spirit and scope of the disclosure as defined by the appended embodiments.

The terms "a", "an", "the" and similar referents used in the context of describing the current disclosure (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. All methods described herein may be performed in any suitable order unless otherwise indicated herein or contradicted by context. The use of any and all examples or exemplary language (e.g., "such as") provided herein is intended merely to better illuminate the current disclosure and does not pose a limitation on the scope of any claim. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the current disclosure. Groupings of alternative elements or embodiments disclosed herein are not to be construed as limitations. Each group member may be referred to and claimed individually or in any combination with other members of the group or other elements found herein. It is anticipated that one or more members of a group may be included in, or deleted from, a group for reasons of convenience.

Certain embodiments are described herein, including the best mode known to the inventors for carrying out the current disclosure. Of course, variations on these described embodiments, will become apparent to those or ordinary skill in the art upon reading the foregoing description. The inventor expects skilled artisans to employ such variations as appropriate, and the inventors intend for the current disclosure to be practiced otherwise than specifically described herein. Accordingly, the claims include all modifications and equivalents, or the subject matter recited in the claims as permitted by applicable law. Moreover, any combination of the above described elements in all possible variations thereof is contemplated unless otherwise indicated herein or otherwise clearly contradicted by context.

In closing, it is to be understood that the embodiments disclosed herein are illustrative of the principles of the claims. Thus, by way of example, but not limitation, alternative embodiments may be utilized in accordance with the teachings herein. Accordingly, the claims are not limited to embodiments precisely as shown or described.

Claims

CLAIMS What is claimed is:

1. A light modulating device comprising: a first transparent electrically conductive element; a second transparent electrically conductive element; a light modulating layer disposed between the first transparent electrically conductive element and second transparent electrically conductive element; wherein the light modulating layer comprises a plurality of compartments divided by polymer walls bonded respectively to and between the first transparent electrically conductive element and the second transparent electrically conductive element; and wherein the plurality of compartments comprise a liquid crystal compound.

2. The light modulating device of claim 1, wherein the plurality of compartments forms a pattern of two dimensional repeating polygons, wherein the sides of the polygons are formed by the polymer walls.

3. The light modulating device of claim 2, wherein: the plurality of compartments is formed by exposing a polymerizable liquid crystal composition to ultraviolet light, wherein the polymerizable liquid crystal composition comprises a diffusing reactive monomer and the liquid crystal compound, and the polymerizable liquid crystal composition further comprises a polymerization inhibitor compound, a UV blocker compound, a photoinitiator compound, microsphere spacer beads, or a combination thereof; wherein exposing the polymerizable liquid crystal composition to ultraviolet light through a patterned photomask causes a patterned polymerization of the polymerizable liquid crystal composition to form the polymer walls; wherein the diffusing reactive monomer diffuses more rapidly than the liquid crystal compound so that during the patterned polymerization of the liquid crystal composition, the plurality of the polymer walls incorporate at least 90 wt% of the diffusing reactive monomer and less than 10 wt% of the liquid crystal compound, and the interior of the compartments defined by the polymer walls comprise a residual composition comprising at least 90 wt% of the liquid crystal compound and less than 10 wt% of the diffusing reactive monomer.

4. The light modulating device of claim 3, wherein the diffusing reactive monomer comprises 2-phenoxyethyl acrylate, acryloyl morpholine, acrylic acid, ethylene glycol diacrylate, or a combination thereof.

5. The light modulating device of claim 3 or 4, wherein the diffusing reactive monomer is 2-phenoxyethyl acrylate.

6. The light modulating device of claim 1, 2, 3, 4, or 5, wherein the liquid crystal compound is QYPDLC-8, MLC2132, or a combination thereof.

7. The light modulating device of claim 3, 4, 5, or 6, comprising the polymerization inhibitor compound, wherein the polymerization inhibitor compound is phenothiazine, N- nitroso-N-phenylhydroxylamine aluminum salt, or a combination thereof.

8. The light modulating device of claim 7, comprising the polymerization inhibitor compound, wherein the polymerization inhibitor compound is phenothiazine.

9. The light modulating device of claim 3, 4, 5, 6, 7, or 8, comprising the UV blocker compound, wherein the UV blocker compound is 2,5-bis(5-tert-butyl-benzoxazol-2- yl)thiophene, UV-790, or a combination thereof.

10. The light modulating device of claim 9, comprisingthe UV blocker compound, wherein the UV blocker compound is UV-790.

11. The light modulating device of claim 3, 4, 5, 6, 7, 8, 9, or 10, comprising the photoinitiator, wherein the photoinitiator compound is ethyl (2,4,6-trimethylbenzoyl)phenyl phosphinate.

12. The light modulating device of claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11, further comprising microsphere spacer beads.

13. The light modulating device of claim 12, wherein the microsphere spacer beads have a width of 10 pm.

14. The light modulating device of claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13, further comprising a chiral dopant.

15. The light modulating device of claim 3, 4, 5, 6, 7 , 8, 9, 10, 11, 12, 13, or 14, wherein the diffusing reactive monomer is capable of diffusing about one half the length of one of the compartments within about 1 to about 30 minutes afterthe patterned polymerization begins.

16. The light modulating device of claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15, wherein the polymer walls have a width of about 1 micron to about 100 microns.

17. The light modulating device of claim 16, wherein the polymer walls have a width of about 10 microns to about 55 microns.

18. The light modulating device of claim 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, or 17wherein the polygons have a width of about 10 microns to about 2000 microns.

19. The light modulating device of claim 18, wherein the polygons have a width of about

100 microns to about 400 microns.

20. A polymerizable liquid crystal composition comprising: about 10 wt% to about 50 wt% of diffusing reactive monomer; about 90 wt% to about 50 wt% of liquid crystal compound; about 0.01 wt% to about 5.0 wt% polymerization inhibitor compound; about 0.01 wt% to about 5.0 wt% ultraviolet light blocker compound; about 0.01 wt% to about 5.0 wt% photoinitiator compound; about 0.01 wt% to about 5.0 wt% microsphere spacer beads; and about 1 wt% to about 10 wt% chiral dopant.

21. A method for making a light modulating device comprising: curing a polymerizable liquid crystal composition between a first transparent electrically conductive element and a second transparent electrically conductive element; wherein the polymerizable liquid crystal composition comprises a diffusing reactive monomer, a liquid crystal compound, a polymerization inhibitor compound, an ultraviolet inhibitor compound, a photoinitiator compound, and microsphere spacer beads; wherein curing the polymerizable liquid crystal composition causes the diffusing reactive monomer to be incorporated, by polymerization reaction, into polymer wall structures between the first transparent electrically conductive element and the second transparent electrically conductive element; wherein the polymer wall structures incorporate at least 90 wt% of the diffusing reactive monomer and less than 10 wt% of the liquid crystal compound therein, wherein the polymer wall structures define a plurality of compartments therein; and wherein the compartments defined by the polymer wall structures contain a composition comprising less than 10 wt% of diffusing reactive monomer subunits and at least 90 wt% of the liquid crystal compound.

22. The method of claim 21, wherein the light modulating device further comprises a voltage source in electrical communication with the first electrically conductive element and the second electrically conductive element, wherein the voltage source may be an AC voltage source, an AC-DC inverter, a battery, or a combination thereof.

23. The method of claim 21, wherein the polymer wall is created by placing a photomask, having defined apertures therein, upon a substrate that is disposed between the first transparent electrically conductive element and a source of photocuring radiation, wherein the photomask apertures define polymer walls and compartments therebetween; applying the photocuring radiation through the photomask apertures upon the polymerizable liquid crystal composition for a period of time and intensity to cure the diffusing reactive monomer and form the polymer wall structures, at least some of the polymer wall structures extending between the first transparent electrically conductive element and the second transparent electrically conductive element and defining a plurality of compartments therein; and removing the photomask.

24. The method of claim 23, wherein the photomask defines dimensions of a polymer wall width of about 1 micron to about 100 microns, and a compartment spacing of about 10 microns to about 2000 microns.