WO2025181674A1 - Electrochromic copolymers - Google Patents

Abstract

An electro-optic element includes a cathodic film disposed on a first electrically conductive layer, an anodic film disposed on a second electrically conductive layer, and an electrolyte layer between the cathodic film and the anodic film. At least one of the cathodic film and the anodic film include a block copolymer. The block copolymer can include a physical crosslinking block that is insoluble in the electrolyte layer and an electrochromic block that can be covalently bonded to the physical crosslinking block. The electrochromic block of the block copolymer is compatible with the electrolyte layer. The block copolymer is immobile on the corresponding one of the first electrically conductive layer and second electrically conductive layer.

Description

ELECTROCHROMIC COPOLYMERS

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to and the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application No. 63/557,737, filed on February 26, 2024, entitled "ELECTROCHROMIC COPOLYMERS," the disclosure of which is hereby incorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

[0002] The present disclosure generally relates to copolymers, and more particularly to long chain block copolymers for electro-optic elements and mediums in film form.

SUMMARY OF THE DISCLOSURE

[0003] According to one aspect of the present disclosure, an electro-optic element includes a cathodic film disposed on a first electrically conductive layer, an anodic film disposed on a second electrically conductive layer, and an electrolyte layer between the cathodic film and the anodic film. At least one of the cathodic film and the anodic film include a block copolymer. The block copolymer includes a physical crosslinking block that is insoluble in the electrolyte layer and an electrochromic block that is covalently bonded to the physical crosslinking block. The electrochromic block of the block copolymer is compatible with the electrolyte layer. The block copolymer is immobile on the corresponding one of the first electrically conductive layer and second electrically conductive layer.

[0004] According to another aspect of the present disclosure, an electro-optic element includes a substrate that has an electrically conductive layer and one of an anodic film and a cathodic film. The electro-optic element also includes an electrolyte layer adjacent one of the cathodic and anodic films. One of the cathodic and anodic films has a block copolymer that includes a physical crosslinking block that is insoluble with the electrolyte layer and an electrochromic block covalently bonded to the physical crosslinking block. The electrochromic block is compatible with the electrolyte layer. [0005] These and other features, advantages, and objects of the present disclosure will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] In the drawings:

[0007] FIG. 1 illustrates a cross-sectional schematic view of an electro-optic element according to aspects of the present disclosure;

[0008] FIG. 2A illustrates a schematic of the chemical structure of an exemplary di-block compound according to an aspect of the present disclosure;

[0009] FIG. 2B illustrates a schematic of the chemical structure of an exemplary tri-block compound according to an aspect of the present disclosure;

[0010] FIG. 3 illustrates a schematic of the chemical structure of an exemplary tri-block compound deposited onto an electrode according to an aspect of the present disclosure;

[0011] FIG. 4A illustrates an exemplary synthetic scheme according to aspects of the present disclosure;

[0012] FIG. 4B illustrates an exemplary synthetic scheme according to aspects of the present disclosure;

[0013] FIG. 5 illustrates an exemplary synthetic scheme according to aspects of the present disclosure;

[0014] FIG. 6 is a proton nuclear magnetic resonance plot according to aspects of the present disclosure;

[0015] FIG. 7 is a proton nuclear magnetic resonance plot according to aspects of the present disclosure;

[0016] FIG. 8 illustrates an exemplary synthetic scheme according to aspects of the present disclosure;

[0017] FIG. 9 is a proton nuclear magnetic resonance plot according to aspects of the present disclosure;

[0018] FIG. 10 illustrates an exemplary synthetic scheme according to aspects of the present disclosure; [0019] FIG. 11 is a proton nuclear magnetic resonance plot according to aspects of the present disclosure;

[0020] FIG. 12 is a cyclic voltammogram plot according to aspects of the present disclosure;

[0021] FIG. 13 is a proton nuclear magnetic resonance plot according to aspects of the present disclosure; and

[0022] FIG. 14 is a transmission with applied voltage plot versus time of a part prepared according to aspects of the present disclosure.

DETAILED DESCRIPTION

[0023] The present illustrated embodiments reside primarily in combinations of method steps and apparatus components related to block copolymers as components for electro-optic elements and electro-optic mediums, as discussed below. Accordingly, the apparatus components and method steps have been represented, where appropriate, by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Further, like numerals in the description and drawings represent like elements.

[0024] As used herein, the term "and/or," when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items, can be employed. For example, if a composition is described as containing components A, B, and/or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.

[0025] In this document, relational terms, such as first and second, top and bottom, and the like, are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises ... a" does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0026] Referring to FIGS. 1-14, reference numeral 10 generally designates an electro-optic element 10 including a cathodic film 74 disposed on a first electrically conductive layer 28, an anodic film 78 disposed on a second electrically conductive layer 46. An electrolyte layer 84 is provided between the cathodic film 74 and the anodic film 78. One of the cathodic film 74 and the anodic film 78 includes a block copolymer 100. The block copolymer 100 includes a physical crosslinking block 130a that is insoluble with the electrolyte layer 84. An electrochromic block 130b is covalently bonded to the physical crosslinking block 130a. The electrochromic block 130b is compatible with the electrolyte layer 84. The block copolymer 100 is immobile on the corresponding one of the first electrically conductive layer and second electrically conductive layer (28, 46).

[0027] Aspects of the present disclosure relate to polymers, and, more particularly, to block copolymers 100 as components for electro-optic elements and electro-optic mediums. The block copolymers 100 of the present disclosure can be used in electro-optic elements 10 and electrochromic devices 14 incorporating such electro-optic elements. By way of introduction, electrochromic devices 14 generally include an electrochromic medium that transitions between an inactivated state in which the electrochromic medium is relatively transparent to light having a wavelength within a predetermined wavelength range and an activated state in which the electrochromic medium has a decreased transmission to light within a predetermined wavelength range when an electrical potential is applied to the electrochromic device. The electrochromic medium includes an anodic component and a cathodic component (also referred to as electroactive components), at least one of which is also electrochromic. The electrochromic electroactive component can provide the electrochromic device 14 with a perceived color when the electrochromic device is in the activated state and/or as the device transitions between the inactivated and activated states.

[0028] While aspects of the present disclosure are described in the context of the electrooptic element 10, aspects of the present disclosure may also be utilized in the context of other electrochromic or electro-optic devices. Non-limiting examples of which include interior and exterior mirror assemblies, bi-stable devices, interior and exterior windows, display screens, heads-up displays, vehicle window assemblies, architectural window assemblies, filter assemblies for eyewear and cameras, and display boards. For example, in the case where the electro-optic element 10 is in the form of a bi-stable device, both sets of chromophores (cathodics and anodics) may be attached to their respective electrodes. In some implementations, one of the chromophores may be in solution and able to diffuse between the adjacent electrode and an opposing electrochromic film/electrode. Further, the block copolymers 100 described herein may be applicable to other devices, including, but not limited to, substrates for an organic light-emitting diode ("OLED"), an organic field-effect transistor ("OFET"), and the like.

[0029] The term "electroactive," as used herein, refers to a material that can undergo a modification in its oxidation state upon exposure to a particular electrical potential difference. The term "electrochromic," as used herein, refers to a material that can exhibit a change in its extinction coefficient at one or more wavelengths upon exposure to a particular electrical potential difference. Electrochromic components, as described herein, include materials whose color or opacity are affected by an electrical current, such that when an electrical field is applied to the material, the color or opacity changes from a first state to a second state (e.g., the inactivated and activated states). Thus, an electrochromic device can exhibit a change in transparency as a result of electrochemical oxidation and reduction reactions that occur between electroactive components (e.g., the anodic components and the cathodic components), in which at least one of the electroactive components is also electrochromic. In other words, when a sufficient electrical potential difference is applied across electrodes of an electrochromic device, the electrochromic medium can shift from a substantially clear state (e.g., a high transmission state, such as the inactivated state) to a substantially dark or darkened state (e.g., a low transmission state, such as the activated state), as well as intermediate states thereto, in the event that one or more of the anodic and the cathodic components are oxidized and reduced, respectively. Specifically, the anodic components are oxidized by donating electrons to the anode and the cathodic components are reduced by accepting electrons from the cathode. Accordingly, the anodic compound, refers to a compound that can reversibly lose an electron(s) upon activation and the cathodic compound, as used herein, refers to a compound that can reversibly gain an electron(s). Some examples of anodic compounds include 5,10-Dihydro-5,10-dialkylphenazines, 10-alkylphenothiazine, ferrocene derivatives, and triphenylamine (TPA) derivatives, vanadium-titanium oxide (VTiOx), metallocenes, 5,10-dihydrophenazines, phenoxazines, carbazoles, triphenodithiazines, triphendioxazines, ferrocene, substituted ferrocenes, phenazine, substituted phenazines, phenothiazine, substituted phenothiazines, including substituted dithiazines, thianthrene and substituted thianthrenes, di-tert-butyl-diethylferrocene, 5,10-dimethyl-5,10- dihydrophenazine (DMP), 3,7,10-trimethylphenothiazine, 2,3,7,8-tetramethoxy-thianthrene, 10-methylphenothiazine, tetramethylphenazine (TMP), bis(butyltriethylammonium)-para- methoxytri phenodithiazine (TPDT), 3,10-dimethoxy-7,14-(triethylammoniumbutyl)- triphenodithazinebis(tetrafluoroborate), and combinations thereof. Some examples of cathodic compounds include l,l'-dialkyl-4,4'-bipyridiniums (viologens), ferrocenium derivatives, substituted viologens, poly dioxythiophenes, tungsten oxides (WO_X), low- dimerizing viologens, substituted low-dimerizing viologens, non-dimerizing viologens or substituted non-dimerizing viologens.

[0030] Referring to FIG. 1, reference numeral 10 generally designates an electro-optic element, which may be included in the electrochromic device 14 as previously described. The electro-optic element 10 can include a first substrate 18 having a first surface 22 and a second surface 26. A first electrically conductive layer 28 is disposed on the second surface 26. A second substrate 34 is provided opposite the first substrate 18 and includes a third surface 38 and a fourth surface 42. A second electrically conductive layer 46 is disposed on the third surface 38. The first substrate 18 and the second substrate 34, along with a sealing member 50 define a chamber 54 for containing an electrochromic medium 58 therein.

[0031] The electro-optic element 10 allows the electrochromic device 14 to be operable between a first state of the electro-optic element 10, which allows electromagnetic radiation having a wavelength within a predetermined wavelength range to pass through, and a second state, in which a portion, or no electromagnetic radiation having a wavelength within a predetermined wavelength range, is transmitted through the electro-optic element 10 (e.g., the electro-optic element 10 becomes generally opaque or partially opaque to electromagnetic radiation having a wavelength within the predetermined wavelength range). The second state of the electro-optic element 10 can be defined relative to the transmissivity of the first state. According to an aspect of the present disclosure, the transmissivity of electromagnetic radiation of a predetermined wavelength or wavelength range through the electro-optic element 10 in the first state may be greater than about 10%, greater than about 12%, greater than about 25%, greater than about 50%, greater than about 55%, or greater than about 85%. Typically, the percentage of reflectance, transmittance, and absorbance of the electro-optic element 10 sum to 100%. In some aspects, the transmissivity of electromagnetic radiation of the predetermined wavelength or wavelength range through the electro-optic element 10 in the substantially second state may be less than about 10%, less than about 1%, less than about 0.1%, less than about 0.01%, or less than about 0.001%.

[0032] The first and/or second substrates 18, 34 can be made of glass, plastic, or other optically transparent or translucent material(s), non-limiting examples of which include borosilicate glass, soda lime glass, or polymeric materials, such as natural and synthetic polymeric resins, plastics, and/or composites. Non-limiting examples of such include polyesters (e.g., PET), polyimides (PI), polycarbonates, polysulfones, polyethylene naphthalate (PEN), ethylene vinyl acetate (EVA), acrylate polymers, as well as cyclic olefin copolymers (COC) (such as those commercially available from TOPAS® Advanced Polymers). In some aspects, both the first and second substrates 18, 34 are made of an optically transparent or translucent material, while, in other aspects, only a single substrate, such as the first substrate 18, is made of an optically transparent or translucent material. The first and second substrates 18, 34 can be made from the same or different materials and may have the same or different dimensions.

[0033] The first and second electrically conductive layers 28, 46 can include one or more layers of an electrically conductive material disposed on the first and second substrates 18, 34, respectively. These layers serve as electrodes (e.g., the cathode and the anode) for the electro-optic element 10. The electrically conductive material(s) of the first and/or second electrically conductive layers 28, 46 may be any suitable material that includes one or more of the following features: (a) substantially transparent to electromagnetic radiation in the visible and/or infrared wavelength ranges; (b) bonds reasonably well to the first and second substrates 18, 34; (c) maintains the bond to the first and second substrates 18, 34 when associated with the sealing member 50; (d) generally resistant to corrosion from materials contained within the electrochromic device 14 or the atmosphere; and/or (e) exhibits minimal diffuse or specular reflectance as well as sufficient electrical conductance. Depending on the application, only one of the first and second electrically conductive layers 28, 46 may be required to be transparent while the other electrically conductive layer 28, 46 may be opaque. In some applications, both the first and the second electrically conductive layers 28, 46 may be transparent. According to some aspects, one of the first and second electrically conductive layers 28, 46, such as the second electrically conductive layer 46, may include a metal reflector or one or more coatings configured as a partially reflective, partially transmissive ("transflective") coating. Inclusion of a metal reflector or a transflective coati ng may render the electrochromic device at least partially reflective. Accordingly, the electrically conductive material(s) forming the first and second electrically conductive layers 28, 46 may be the same or different. Non-limiting examples of electrically conductive material that may be used to form the first and/or second electrically conductive layers 28, 46 can include transparent conductive oxides (TCOs) such as fluorine doped tin oxide (FTO), for example TEC™ glass, indium tin oxide (ITO), doped zinc oxide, indium zinc oxide (IZO), aluminum doped zinc oxide (AZO), and metal oxide/metal/metal oxide (including, where the metal oxide can be substituted with metal carbide, metal nitride, metal sulfide, etc.).

[0034] Still referring to FIG. 1, the sealing member 50 can traverse, or extend along, and cooperate with an approximate perimeter of, the first and second substrates 18, 34 to define the chamber 54 as substantially hermetic. The sealing member 50 may be disposed around a perimeter of the electrochromic medium 58 (e.g., extending from the second surface 26 to the third surface 38). The sealing member 50 may be in the form of any suitable seal type and material. For example, the sealing member 50 may include thermoset epoxy. [0035] In some examples, first and second annular bands 62, 64 of highly conductive material are optionally deposited around the perimeter of the first and second substrates 18, 34, respectively, and electrically-conducting structures 68 (e.g., conductive tape, clips, traces, or wires) are secured to the highly conductive material and spatially separated from one another. The electrically-conducting structures 68 may supply an electrical voltage to the first and second annular bands 62, 64 of highly conductive material to create a voltage across the electro-optic element 10, thereby reversibly driving the electro-optic element 10 between states, such as the substantially dark and substantially clear states. The first and second annular bands 62, 64 of highly conductive material may include, but is not limited to, silver, gold, copper, or aluminum (such as, for example, in a form of metallic flakes or particles dispersed in a hosting material).

[0036] The electro-optic element 10 includes the electrochromic medium 58. The electrochromic medium 58 includes at least one cathodic component and at least one anodic component. The anodic and cathodic components may, alternatively, be referred to as chromophores, electrochromic molecules, or electrochromic polymers. According to the present disclosure, the anodic and/or cathodic components may be a polymer. In some aspects, both the cathodic and anodic components are electroactive and at least one of the anodic component or cathodic component is electrochromic. Further, the components of the electrochromic medium 58 can be utilized in film form (e.g., a solid polymer or a gel polymer), gel form, or solution form in the electro-optic element 10. In film examples, the electrochromic medium 58 may include one or more layers of material(s) attached directly to an electrically conductive layer (e.g., 28, 46) or confined in close proximity to an electrically conductive layer (e.g. ,28, 46), which remains attached or confined when components thereof are oxidized and/or reduced.

[0037] As illustrated in FIG. 1, the electrochromic medium 58 utilized with the electro-optic element 10 includes both a cathodic film 74 and an anodic film 78. An electrolyte layer 84 separates the cathodic and anodic films 74, 78. In this way, the cathodic film 74, anodic film 78, and electrolyte layer 84 define the electrochromic medium 58. In such an example, the cathodic film 74 may contain the cathodic component on the backbone of the polymeric chains, and/or as pendant groups (e.g., side chain modifications), while the anodic film 78 may contain the anodic component on the backbone of the polymeric chains, and/or as pendant groups, which will be discussed further with respect to FIGS. 2A-3.

[0038] The electrolyte layer 84 may be a gel (e.g., a semi-liquid configured to permeate the cathodic and anodic films 74, 78) or a polymeric electrolyte configured as a thin film electrolyte. In examples utilizing a polymeric electrolyte as the electrolyte layer 84, the polymeric electrolyte may include a polymer, such as polymethyl methacrylate ("PMMA"), poly(styrene-ran-ethylene), polystyrene-Woc -poly(ethylene-ran-butylene), polyfstyrene- ran-ethylene), polystyrene-b/ock-poly(ethylene/butylene)-b/ock-polystyrene, polyfethylene glycol), polyfmethyl acrylate), other polymer electrolytes and/or combinations thereof and various plasticizers, such as propylene carbonate, ethylene carbonate, dimethyl carbonate, and the like. The electrolyte layer 84, including plasticizers included associated therewith, may partially permeate the cathodic and anodic films 74, 78.

[0039] The anodic film 78 of the electrochromic medium 58 can include one or more anodic components. Non-limiting examples of anodic components include tri-phenyl amines (TPAs), vanadium-titanium oxide (VTiOx), metallocenes, 5, 10-dihydrophenazines, phenoxazines, carbazoles, triphenodithiazines, triphendioxazines, ferrocene, substituted ferrocenes, phenazine, substituted phenazines, phenothiazine, substituted phenothiazines, including substituted dithiazines, thianthrene and substituted thianthrenes, di-tert-buty I- diethylferrocene, 5,10-dimethyl-5,10-dihydrophenazine (DMP), 3,7,10- trimethylphenothiazine, 2,3,7,8-tetramethoxy-thianthrene, 10-methylphenothiazine, tetramethylphenazine (TMP), bis(butyltriethylammonium)-para-methoxytriphenodithiazine (TPDT), 3,10-dimethoxy-7,14- (triethylammoniumbutyl)-triphenodithazinebis(tetrafluoroborate), and combinations thereof.

[0040] The cathodic film 74 of the electrochromic medium 58 can include one or more cathodic components, which can include a reducible compound. Non-limiting examples of cathodic components include viologens, substituted viologens, poly dioxythiophenes, tungsten oxides (WO_X), low-dimerizing viologens, substituted low-dimerizing viologens, nondimerizing viologens or substituted non-dimerizing viologens. Illustrative viologens include, but are not limited to, methyl viologen, octyl viologen, benzyl viologen, polymeric viologens, and the viologens described in U.S. Pat. Nos. 4,902,108; 6,188,505; 5,998,617; 9,964,828; 10,481,456; and 6,710,906, which are herein incorporated by reference in their entirety. In one aspect, the cathodic component is selected from a viologen, a low-dimerizing viologen, a non-dimerizing viologen, a substituted viologen, a di-acrylate viologen, a cathodic di-vinyl viologen, a cathodic di-vinyl ether viologen, a cathodic di-epoxy viologen, a cathodic di- oxetane viologen, a cathodic di-hydroxy viologen, or a combination thereof. In some examples, the electrochromic medium may include a combination of two or more cathodic components to provide the electrochromic medium 58 with a desired color when activated. Examples of suitable combinations of anodic and cathodic components can be found in U.S. Patent No. 6,020,987, entitled "Electrochromic Medium Capable of Producing a Pre-Selected Color," issued February 1, 2000, the contents of which are incorporated herein by reference in its entirety.

[0041] The electrolyte layer 84 of the electrochromic medium 58 may also include one or more electrolytes, which may be in the form of a solvent and a salt. The salt may be a metal salt or an ammonium salt. Non-limiting examples of suitable solvents for use in the electrolyte include: 3-methylsulfolane, dimethyl sulfoxide, dimethyl formamide, tetraglyme, and other polyethers; alcohols, such as ethoxyethanol; nitriles, such as acetonitrile, glutaronitrile, 3- hydroxypropionitrile, and 2-methylglutaronitrile; ketones, including 2-acetylbutyrolactone and cyclopentanone; cyclic esters including beta-propiolactone, gamma-butyrolactone, and gamma-valerolactone; carbonate esters including propylene carbonate (PC) and ethylene carbonate; and homogenous mixtures thereof. Non-limiting examples of suitable salts include: metal or ammonium salts, such as lithium triflate, lithium perchlorate, sodium triflate, sodium perchlorate, etc., Li⁺, Na⁺, K⁺, NR (where each R' is individually H, alkyl, or cycloalkyl), or the following anions F“, Cl", Br“, I", BF4", PFs ", SbFs ", AsFg", CIO4 , SO₃CF₃“, NfCFsSO?)?", C(CF₃SO2)₃ ", NfSOjCjFsh", AI(OC(CF₃)₃)₄", or BAr₄", where Ar is an aryl or fluorinated aryl group such as, but not limited to, CgHs, 3,5-(CF₃)2CsH₃, or CgFs.

[0042] While the electrochromic medium 58 utilized with the electro-optic element 10 is illustrated as including a cathodic film 74 and an anodic film 78, aspects of the present disclosure can be applicable to any suitable electrochromic medium 58 utilized with the electro-optic element 10 (e.g., a full film device). In such an example, an electro-optic film may contain both the anodic component and the cathodic component on the backbones of a polymeric chain, and/or as pendant groups. In the electro-optic film example, the anodic component and the cathodic component are both positioned on the same copolymer chains. [0043] Recent synthetic research efforts toward polymer designs have led to a need to tailor such polymers for enhanced process handling. Polymers can be formulated to include certain properties that impart beneficial characteristics for process handling, such as certain molecular weights and solvent compatibility factors. For example, a properly formulated polymer can enhance solution quality for various coating techniques, including, but not limited to, slot die, gravure, inkjet, spin, spray coating, etc.

[0044] Creating copolymers 100 with specific functionalities imparted within each block allows the copolymer 100 to be produced as a single, bulk material, which benefits overall prepolymerized processability and the resulting morphology of the copolymer 100. In this way, the functionalities imparted within each block are coupled into the chemistry of the copolymer 100 itself (e.g., side-chain modification^]) as opposed to merely being mixed in a solution. These block copolymers 100, such as di-block copolymers and tri-block copolymers, allow fine control over individual blocks to tailor molecular weights at each unit and/or incorporate a variety of functionalities (e.g., ion conduction, chromophores). Further, the incorporation of specific functionality into the chemistry (e.g., formulating the copolymer as a bulk material rather than a polymer blend) is beneficial to the electro-optic element 10 for improved electrochromic device speed, electrochromic response time, and device stability and durability. Further, block copolymers of the present disclosure decrease susceptibility of the electro-optic element 10 to degradation, thereby providing a more durable device. Conventional electroactive or electrochromic thermosets may tend to have a relatively low viscosity and must undergo a B-staging or partial polymerization to achieve a viscosity suitable for the various coating methods previously described. Further, once the conventional coating material is cast or applied to a substrate, the coating material must cure through additional crosslinking to form a film. This reaction can be sensitive to the atmosphere, specifically to moisture or oxygen. In many cases, moisture can react with the crosslinking agent, rendering it ineffective. Oxygen or electroactive elements can quench (e.g., stop) radical initiated or propagation reactions in other curing mechanisms (e.g., radical initiated UV-curing). Even further, a rapidly drying film can cause limited functional group mobility within a carrier solvent, resulting in incomplete crosslinking due to the inability of reactant centers to reach each other. In addition, added time is required for the reaction to reach completion, which may not be desirable in a manufacturing process.

[0045] Referring now to FIGS. 2A and 2B, aspects of the present disclosure relate to formulating block copolymers 100, which may include physical crosslinking blocks and electroactive (e.g., electrochromic) blocks. These copolymers 100 include multiple blocks of distinct repeat units. A block may be a region within a polymer chain of a distinct chemical makeup different that differs from other blocks within the copolymer 100. These block copolymers 100 may form the electrochromic medium 58, the electro-optic film 70, or components thereof, such as the cathodic film 74, the anodic film 78, and/or the electrolyte layer 84. However, it is within the scope of aspects described herein for the block copolymers 100 of the present disclosure to be incorporated into any suitable medium.

[0046] FIG. 2A illustrates a schematic of the chemical structure of an exemplary di-block compound 110, or block copolymer unit that includes two monomers 130. The di-block compound 110 can be in the form of a copolymer including an "a" monomer and a "b" monomer. In some aspects, the "a"' monomer represents the physical crosslinking block, while the "b" monomer represents the electrochromic block. In some examples, the physical crosslinking blocks (e.g., 130a) may include styrene blocks, ethylene blocks, propylene blocks, acrylate blocks, ether blocks, ester blocks, acrylamide blocks, and the like. In some examples, the electrochromic-functionalized blocks (e.g., 130b) may include methacrylate blocks, acrylate blocks, ether blocks, ester blocks, acrylamide blocks, and the like. The electrochromic blocks 130b include chromophores, which may be cathodics, anodics, or both anodics and cathodics. In specific implementations, the electrochromic block can function as a linker between two physical crosslinking blocks. The physical crosslinking blocks 130a tend to aggregate with one another and remain insoluble in the electrolyte medium (e.g., electrolyte layer 84).

[0047] FIG. 2B illustrates a schematic of the chemical structure of an exemplary tri-block compound 120, or block copolymer unit that includes three monomers 130. The tri-block compound 120 can be in the form of a copolymer including an "a" monomer, a "b" monomer and an "a"' monomer. In some aspects, the "a" monomer and the "a"' monomer represent the physical crosslinking blocks 130a, 130a'. The physical crosslinking blocks 130a, 130a', (e.g., styrene blocks) can be chemically identical, but the length of each physical crosslinking block 130a, 130a' (i.e., number of repeat units) may or may not be identical. In this way, the physical crosslinking blocks 130a, 130a' may or may not be the same/similar in value. Due to the similarity in chemical identity, the physical crosslinking blocks 130a, 130a' tend to aggregate with other physical crosslinking blocks 130a, 130a' on different copolymer chains.

[0048] According to aspects of the present disclosure, the monomers forming polymer block 130 (e.g., "a" 130a, "b" 130b, "a"' 130a') which then form the di-block and/or tri-block compound 110, 120 can include R groups (e.g., Rl, R2, R3, RCTA , ZCTA etc.), which may include any side-chain modification, chain transfer agent (CTA), or polymerizable compound suitable for use in polymers. RCTA and ZCTA are components of the chain transfer agent. In this way, the copolymer 100 grows between RCTA and ZCTA. The CTA is part of a reversible additionfragmentation chain transfer (RAFT) process and may provide increased control over the molecular weight and polydispersity of the resulting linear compound. This living polymerization can yield multiple copolymer combinations such as di-block and/or tri-block compounds 110, 120 (e.g., AB, ABA, or BAB) with controlled lengths for each block or monomer. A variety of CTA materials may be used, including, but not limited to, thiocarbonylthio compounds, such as dithioesters, dithiocarbamates, trithiocarbonates, xanthates, and the like. According to aspects of the present disclosure, the CTAs may be substituted with other thiocarbonylthio compounds, such as dithioesters, dithiocarbamates, trithiocarbonates, xanthates. Specific examples of such include 1-methyl-l-phenylethyl ester, 1-cyano-l-methylethyl ester, 2-(Dodecylthiocarbonothioylthio)-2-methylpropionic acid but are not limited to such. Accordingly, the CTA may include RCTA and ZCTA, which are components of varying compositions.

[0049] In some aspects, the R groups (e.g., side chain modifications Rl, R2, R3) provide specific functionalities providing a benefit (e.g., a desired characteristic) to the copolymer 100, such as a solution-enhancing property. In non-limiting examples, specific functionalities may include increased processability, ionic charge, adhesion, advantageous morphology characteristics, light absorbance, light stabilizing, thermal stabilizing, antioxidants, oxygen scavenging, thickening, viscosity modifying, tinting/coloring, redox buffering, and the like. Further, the R group may be in the form of a compound that configures the copolymer 100 as an electroactive material (e.g., cathodic/anodic compounds). In this way, the di-block compound 110 or tri-block compound 120 of the present disclosure may include R groups providing specific, desired, functionalities and/or R groups provided to enable further polymerization of the polymer and/or include electroactive properties, examples of which are described below.

[0050] The di-block compound 110 and tri-block compound 120 of FIGS. 2A and 2B may include RCTA and ZCTA groups (typically from a CTA) which may be chosen from any suitable CTA or conversion of CTAs. Likewise, Rl, R2 and R3 groups may be any suitable compound(s). It is understood that the number of R groups depends on the specific di-block or tri-block formula. As such, di-block compounds 110 and tri-block compounds 120 of the present disclosure may include less than or more than the 3 R groups shown in FIGS. 2A and 2B. Further, an R or Z group may function as a cap, a linker, or may be reacted further with additional compounds.

[0051] Accordingly, the exemplary di-block compound and tri-block compound 110, 120 disclosed herein may include different materials conjugated into the chemistry (e.g., as side chain modifications or on the polymer backbone) of the copolymers 100, which provide a solution-enhancing property (e.g., functional moieties). A solution-enhancing property may impart a characteristic to the carrier solvent, copolymer 100 itself, and/or the electrochromic medium 58 that provides a benefit to the same. Again, non-limiting examples of beneficial properties include increased processability, viscosity, adhesion, or advantageous morphology characteristics. The exemplary di-block and tri-block compounds 110, 120 disclosed herein allow for creating the copolymers 100 to include desired properties, or characteristics, such as UV-visible-NIR absorbance in the dark state. Other examples of characteristics/features of the di-block and tri-block compounds 110, 120 may include are, light absorbing, light stabilizing, thermal stabilizing, antioxidants, oxygen scavengers, thickeners, viscosity modifiers, tint/color providing agents, redox buffers, and the like. In specific implementations, block 130a is in the form of a repeat unit that is insoluble within the electrolyte layer 84 or the electrolyte's plasticizer, rendering the corresponding copolymers 100 immobile on the electrode. Also, in specific implementations, block 130b is in the form of a repeat unit that makes the block highly flexible, soluble within the electrolyte solution 84, and able to be functionalized with electrochromic molecules either before the polymerization or afterwards. Due to the soluble nature of the electrochromic blocks 130b with the electrolyte's plasticizer or electrolyte layer 84, ionic and electronic charge transport is enabled.

[0052] Referring now to FIG. 3, the cathodic film 74 (which may be a gel layer) may include a cathodic copolymer that is disposed on the first electrically conductive layer 28. In some aspects, the cathodic copolymer is dispersed in a carrier solvent 72 when applied to the first electrically conductive layer 28 during production of the electro-optic element 10. In some aspects, the carrier solvent 72 is a coating solvent which may not be present in the cathodic film 74 in its final form. Further, the carrier solvent 72 may be capable of dissolving all of the blocks, physical crosslinking blocks 130a and electrochromic blocks 130b, while only the electrochromic blocks 130b will be miscible with the electrolyte layer 84, including the electrolyte's plasticizers included associated therewith. Thus, the physical crosslinking blocks 130a are not miscible or dissolvable in the electrolyte layer 84, including the electrolyte's plasticizers included associated therewith. Accordingly, the blocks (e.g., 130a, 130b) of the copolymer 100 are soluble within the carrier solvent 72 to deposit an electrochromic film (e.g., the cathodic film 74 or anodic film 78) onto an electrode. In some aspects of the present disclosure, after evaporation of the carrier solvent 72 at least a portion of the cathodic copolymer 100 disposed on the first electrically conductive layer 28 is immobile when in contact with the electrolyte layer 84, including the electrolyte's plasticizers. In this way, when the electro-optic element 10 is formed, and the cathodic film 74 is adjacent to the electrolyte later 84, the cathodic film 74 does not permeate into the electrolyte layer 84 as it is immobile on the first electrically conductive layer 28.

[0053] Likewise, the anodic film 78 (which may be a gel layer) may include an anodic copolymer that is disposed on the second electrically conductive layer 46. In some aspects, the anodic copolymer is dispersed in the carrier solvent 72 when applied to the second electrically conductive layer 46 during production. In specific examples, after evaporation of the carrier solvent 72, at least a portion of the anodic copolymer is immobile when adjacent to the electrolyte layer 84, including the electrolyte's plasticizer. In this way, when the electrooptic element 10 is formed, and the anodic film 78 is adjacent to the electrolyte later 84, the anodic film 78 does not permeate into the electrolyte layer 84 as it is immobile on the second electrically conductive layer 46 similar to the method for forming the cathodic film 74 as previously described herein.

[0054] Still referring to FIG. 3, deposition of these block copolymers 100 onto an electrode (e.g., 28, 46) followed by removal of the carrier solvent 72 results in a film with electroactive regions (e.g., the cathodic and anodic films, 74, 78). These films are able to transport ions and electronic charge and are bound together by regions of aggregated polymer (e.g., di-block and/or tri-block compounds 110, 120). By separating the crosslinking portion (e.g., 130a) of the copolymer from the electroactive region (e.g., 130b), regions within the film with a higher density of electroactive moieties can be achieved, which improves ionic and electronic charge transport. Complete dissolution of the copolymer into the carrier solvent 72 yields a solution of controlled viscosity and parameters that can be tuned for various deposition methods (e.g., spray coating, spin coating, gravure printing, slot die, etc.). After deposition of polymer films (e.g., the cathodic and anodic films, 74, 78) onto electrodes, morphological modification of the copolymers can be performed through methods such as solvent or thermal annealing, which facilitates phase segregation of the various copolymer blocks and better aggregation of the physical cross-linked regions (e.g., 130a).

[0055] In some aspects, the electro-optic element 10 may include a pair of electro-optic subassemblies in the form of a cathodic sub-assembly and an anodic sub-assembly, which include the first substrate 18 and the second substrate 34. For example, the first substrate 18 can include the cathodic film 74 while the second substrate 34 can include the anodic film 78. Additionally, one or both of the cathodic sub-assembly and the anodic sub-assembly can include additional layers, non-limiting examples of which include polarizers, anti-reflective layers, filters, resistive layers, ultraviolet light reflecting or absorbing layers, infrared light reflecting layers, gas diffusion barrier layers, water vapor diffusion barrier layers, etc. In some examples, the cathodic film layer 74 and/or the anodic film layer 78 can include an ion conduction layer disposed thereon. The ion conduction layer can be configured to be conductive to positively or negatively charged ions, such as H⁺ or Li⁺, but is low in electron conductivity in comparison. In this implementation, the electro-optic sub-assemblies are prepared independently and later combined to form the electro-optic element 10. However, due to the rapid electroactivity and stability to loss of charge density exhibited by the cathodic film layer 74 and/or the anodic film layer 78 including the block copolymer 100 of the present disclosure, an ion conduction layer may be omitted.

[0056] The following examples describe various features and advantages provided by the disclosure and are in no way intended to limit the invention and appended claims. As used in the examples herein the following abbreviations are explained: RAFT - reversible additionfragmentation chain transfer polymerization, MeOH - methanol, ROH - generic alcohol functionalized molecule, RNH? - generic primary amine functionalized molecule, MA - methyl acrylate, PMA - polyfmethyl acrylate), PS - poly(styrene), PFcA - polyfferrocenyl acrylate), TBD - l,5,7-Triazabicyclo[4.4.0]dec-5-ene, AIBN - 2,2'-Azobis(2-methylpropionitrile), Triflimide or NTF? - Bis(trifluoromethanesulfonyl)imide, TLC - thin layer chromatography, ¹H-NMR - proton nuclear magnetic resonance, GPC - gel permeation chromatography, b - block copolymer, r - random copolymer, MW - molecular weight, M_n - number average polymer molecular weight, M_w - weight average polymer molecular weight.

EXAMPLES

[0057] Referring to FIGS. 4A and 4B, exemplary synthetic scheme 200, 250 are illustrated wherein block copolymers of polystyrene and polyfmethyl acrylate) which were prepared using a RAFT polymerization and were then used to prepare the electroactive block (e.g., 130b). The copolymer is not limited to linear polymers but can take on many architectures, such as star polymers or brush polymers. As shown in FIG. 4A, in scheme 200, the polyfmethyl acrylate) block is modified via a base- or acid-catalyzed transesterification reaction that drives off methanol as an alcohol functionalized molecule (e.g., shown as R in FIG. 4A) is attached in a post-polymerization modification. As shown in FIG. 4B, in scheme 250, the polyfmethyl acrylate) block is modified via a base-catalyzed amidation reaction that drives off methanol as an amine functionalized molecule (e.g., shown as R in FIG. 4B) is attached in a postpolymerization modification. To note, multiple alcohol and/or amine functionalized molecules may be substituted simultaneously. Likewise, either the electroactive block 130b or the physical crosslinking block 130a may be synthesized via scheme 200, 250 or similarto produce pendant molecules that provide a specific functionality such as, but not limited to: ionic charge (e.g., the pendant molecule is a charged species), adhesion, advantageous morphology characteristics, thermal initiating, light absorbance, light stabilizing, thermal stabilizing, antioxidants, oxygen scavenging, thickening, viscosity modifying, solubilizing, tinting/coloring, redox buffering, and the like. Optionally, instead of a post-polymerization modification to prepare the electroactive block (e.g., 130b) of the copolymer, 130b can be prepared directly by a living polymerization of electroactive monomers along with other monomers that provide ionic charge (e.g., the pendant molecule is a charged species), adhesion, advantageous morphology characteristics, thermal initiating, light absorbance, light stabilizing, thermal stabilizing, antioxidants, oxygen scavenging, thickening, viscosity modifying, solubilizing, tinting/coloring, redox buffering, and the like if the monomers are compatible with the polymerization chemistry.

[0058] Example 1

[0059] FIG. 5, pertaining to Example 1, illustrates an exemplary synthetic scheme, 300, for synthesizing triblock copolymer poly(styrene-b-methyl acrylate-b-styrene) (PS226-b-PMAs73-b- PS357), 1, by RAFT polymerization. As noted herein, subscripts noted with respect to the copolymers listed throughout the Examples illustrate a calculated number of repeat units for the corresponding compounds.

[0060] Procedure: A typical preparation of the tri-block copolymers occurred in three steps using a RAFT polymerization Polystyrene initial block, la: Styrene was run through a 6cm plug of basic alumina prior to use. An oven dried lOOmL Schlenk tube was charged with styrene (40g, 384mmol), 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid (0.134g,

0.37mmol), and 2,2'-Azobis(2-methylpropionitrile) (AIBN) (17mg, 0.106mmol) under nitrogen. The solution was bubbled with argon for 45 minutes. The tube was sealed then placed in a 70°C silicone oil bath for 18 hours at which point it was rapidly cooled in liquid nitrogen then slowly precipitated into 800mL of stirred methanol to yield a light-yellow solid. Collected solid by filtration then washed with 200 mL of methanol. The solid was dissolved in 90mL of toluene then reprecipitated into 900mL of rapidly stirred methanol. The light-yellow solid was once again collected by filtration, washed with 200mL of methanol, then dried under vacuum at 40°C for 16 hours. Yield: 12.8g = 33.5%. M_n 23.6k, M_w 26.4k by GPC.

[0061] Adding second polyacrylate block, lb, to polystyrene block la: Methyl acrylate (MA) was run through a 4cm plug of basic alumina prior to use. An oven dried lOOmL Schlenk tube was charged with the polystyrene block la (3.0g, 0.22mmol) and MA (30g, 348 mmol) in 20mL anhydrous toluene under nitrogen. AIBN (lmg/mL toluene, 3.0mg, 0.018mmol) was added. The solution was bubbled with argon for 20 minutes after cooling slightly in liquid nitrogen to limit evaporation. The tube was sealed and placed in a 60°C oil bath. After three hours, the viscous reaction mixture was rapidly cooled in liquid nitrogen then slowly poured into 600mL of rapidly stirred methanol to yield an off-white solid. The solvent was decanted. The polymer was washed with hot methanol (2x200mL) then dried under vacuum at 40°C for 72 hours. Yield: 10.3g - 24.5%. Based on ¹H-NMR, the PMA:PS ratio present in the copolymer (PS226-b- PMA673 was 2.98:1.00. Estimated total molecular weight by ¹H-NMR: 81.6k. FIG. 6 is a proton nuclear magnetic resonance plot (¹H-NMR) of copolymer lb in CDCh.

[0062] Adding third block polystyrene, lc, to block copolymer: Styrene was run through a 5cm plug of basic alumina prior to use. An oven dried 100mL Schlenk tube was charged with block copolymer of la and lb, styrene (9.1g, 87mmol), AIBN (2.0mg, 0.012 mmol) and 15mL anhydrous toluene under nitrogen. The reaction mixture was bubbled with argon for 30 minutes then sealed and stirred until the polymer dissolved. It was then placed into a 70°C silicone oil bath. After 19.5 hours the mixture was rapidly cooled in liquid nitrogen then slowly poured into 550mL of rapidly stirred methanol resulting in precipitation of an off-white polymer. The polymer was collected by filtration, washed repeatedly with a total of 200mL of methanol, then dried overnight under vacuum at 40°C for 24 hours. The final yield was 3.3g - 14.2%. Based on ¹H-NMR, the PMA:PS ratio present in the copolymer was 1.15:1.00. FIG. 7 is a proton nuclear magnetic resonance plot (¹H-NMR) of the product of Example 1 in CDCh.

[0063] Final molecular weight was based on GPC (M_n) for block 1 and ¹H-NMR for the remaining blocks. The final polymer parameters are listed in Table, 1, below.

[0064] Table 1

[0065] Example 2

[0066] FIG. 8, pertaining to Example 2, illustrates an exemplary synthetic scheme, 400, for synthesizing PSi52-b-(PMAi59-r-PFcAi33)-b-PS47 via transesterification of 1, PSi52-b-PMA292-b- PS47 with ferrocenemethanol.

[0067] Procedure: An oven dried 25mL oven dried Schlenk was charged with 1 (0.50g, 0.19mmol MA), ferrocenemethanol (0.40g, 1.84mmol), and l,5,7-Triazabicyclo[4.4.0]dec-5- ene (TBD) (39mg, 0.28mmol) in 15 mL anhydrous toluene under nitrogen. The flask was fitted with a short path condenser and placed into a 120°C oil bath under a gentle flow of nitrogen to remove methanol. After 24 hours, the reaction mixture was allowed to cool to RT the precipitated into 300mL rapidly stirred hexane. Collected the solid by filtration and washed with hexane (3xl00mL). Yield: 0.63g of a light-yellow powder very prone to static. Using GPC to calculate the MW of the first block and NMR for the remaining blocks, there was a 45% conversion of methyl acrylate groups to ferrocenylmethyl acrylate. The final polymer parameters for PSi52-b-(PMAi59-r-PFcAi33)-b-PS47 are listed in Table, 2, below. FIG. 9 is a proton nuclear magnetic resonance plot (¹H-NMR) of the product of Example 2 in a mixture of 1:1 Acetone-cfe/CC

[0068] Table 2

[0069] Example 3

[0070] Synthesis of Triethylammoniumhexan-6-ol triflimide.

[0071] Procedure: A 500mL 2-neck RBF was charged with 6-chlorohexanol (20.5g, ISOmmol) and triethylamine (15.3g, 300mmol) in 50mL anhydrous toluene under a blanket of nitrogen. Fitted the flask with a condenser then heated to 65°C for 10 days. Two layers had formed. The reaction mixture was cooled to RT and lOOmL of water was added to the mixture. The upper organic fraction was separated and extracted with an additional 50mL of water. The aqueous fractions were combined then washed with 50mL of toluene. To the aqueous fraction, 50g (174 mmol) of lithium bis(trifluoromethane)sulfonimide in 75mL of water was added to form a white, cloudy mixture. An amber oil separated from the aqueous mixture. The oil was collected, washed with water (2xl00mL), then dried under a strong purge of nitrogen at 80°C.

[0072] Yield: 24.2g (MW 482.49g/mol, 50.2mmol) = 33.5% yield.

[0073] Example 4

[0074] FIG. 10, pertaining to Example 4, illustrates an exemplary synthetic scheme, 500, of transesterification of PS226-b-PMAs73-b-PS357 triblock copolymer, 1 (PMA:PS ratio of 1.15:1.00), with a 9:1 ratio of dineopentylphenazine hexanol/triethvlammoniumhexanol, 3. [0075] Procedure: An oven dried, 50mL round bottom flask was charged with 1 (1.92g, 9.4mmol MA), 5,10-dineopentyl-2-(hexan-6-ol)phenazine (4.35g, 10.3mmol), triethylammoniumhexanol triflimide, 3 (0.55g, l.lmmol), and TBD (0.24g, 1.7mmol) in a mixture of lOmL anhydrous DMSO and 5mL anhydrous toluene. The flask containing the dark red reaction mixture (green fluorescence) was fitted with a short path condenser under a gentle nitrogen purge and outfitted with a vent needle to aid in the removal of any methanol that was generated. The flask was placed in a 120°C silicone oil bath for 114 hours. The reddish polymer solution was cooled to room temperature then slowly precipitated into 200mL rapidly stirred methanol to yield a light tan solid which was collected by filtration, washed with 300mL of methanol, then dried under vacuum at 40°C overnight. Yield: 4.8g. TLC of the product (SiOz, 2:2:1 CFhCN/methanol/NI- CI mobile phase) showed no signs of the free phenazine (Rf 0.94) within the polymer mixture (Rf 0). FIG. 11 is a proton nuclear magnetic resonance plot (¹H- NMR) of the product of Example 4 in a 1:1 mixture of Acetone-c/s/CCk. The original methyl (- O-C/-/3) of methyl acrylate at 3.66ppm is reduced in area and partially replaced with a new peak of similar area at 3.55ppm from the methylenes (-O-C/-/2-C-) of the pendant phenazine and ammonium groups.

[0076] Example 5

[0077] Transesterification of PS226-b-PMAs73-b-PSi77 triblock copolymer, 1, with a 9:1 ratio of 5,10-dineopentyl-2-hexan-6-olphenazine/triethylammoniumhexanol triflimide, 3.

[0078] Procedure: Followed a similar procedure to 4 using a starting polymer 1, PS226-b- PMAs73-b-PSi77, with a PMA:PS ratio of 1.67:1.

[0079] Example 6

[0080] Measuring the electrochemical properties of synthetic scheme 500, Example 4.

[0081] Procedure: A polymer solution was prepared by dissolving a few mg of the product of synthetic scheme 500, Example 4, into 2mL of anhydrous THF. 250pL of the polymer solution was drop cast onto a 3" x 3" glass slide coated with half-wave indium tin oxide (HW-ITO). The slide was covered with a dish allowing the solvent to slowly evaporate overnight. The film was then completely dried under vacuum for 72 hours at 40°C. The ITO slide was clamped into an electrochemical paint test cell with a working electrode area of 6.35cm². A silver wire was used as a reference electrode (Ag/Ag⁺). The counter electrode was Pt mesh. The electrolyte was 0.2M tetraethylammonium tetrafluoroborate in propylene carbonate. The scan rate was lOmV/s. A cyclic voltammetry scan (-0.3V> 1.20V>-0.3V, 10 cycles) very clearly showed two well-defined oxidation peaks of the attached phenazine. In addition, the current levels and peak shapes were stable across all ten cycles indicating no loss of electroactive material from the electrode surface. FIG. 12 is cyclic voltametric plot of the product of Example 6.

[0082] Example 7

[0083] Using the polymer from example 5, a functioning electrochromic part was built and tested for speed and memory.

[0084] Cathode: A cathode coating solution was prepared from l,l'-bis(hexan-6-ol)-4,4'- bipyridinium triflimide (0.749g), octamethyl dihexan-6-ol ferrocenium tetrafluoroborate (0.029g), Desmodur N3300A (0.303g), Teco Glide 410 (l.Omg), and dibutyltin diacetate (0.6 wt. % in propylene carbonate, 69pL) dissolved in 3-methoxypropionitrile (2.55g), propylene carbonate (1.37g). Air plasma treated 3"x3" HW-ITO electrodes were coated with the polymer solution using a #6 Mayer rod. The films were dried in an oven at 65°C under nitrogen for 1 hour then stored under nitrogen. The average film thickness was 1.5-1.6 (pM - micron).

[0085] Anode: Prepared a 10 wt.% solution of 5 (1.00g) in anhydrous toluene (9.00g). The solution was bubbled with argon for 1 minute as it was stirred followed by filtration through a 0.45mM PTFE syringe filter. Air plasma treated 3"x3" HW-ITO electrodes were coated with the polymer solution using a #8 Mayer rod. The films were dried in an oven at 65°C under nitrogen for 1 hour then stored under nitrogen. The films were smooth and defect free with an average thickness of 1.2-1.3 (pM - micron). The films were solvent annealed by placing them in a sealed container saturated with toluene vapor for two hours then transferred to a nitrogen purged cabinet to evaporate any remaining solvent.

[0086] Electrolyte: A urethane cross-linkable gel electrolyte was prepared. The polyol was a 15 wt. % 1:10 random copolymer of 2-hydroxyethyl methacrylate/methyl acrylate in propylene carbonate. The electrolyte solution was prepared by mixing isophorone diisocyanate (IPDI) (0.061g), tetraethylammonium triflimide (TEA.NTf?) (2.462g), dibutyltin diacetate (0.6 wt. % in propylene carbonate, 20 pL), polyol solution (6.72g), and propylene carbonate (36.757g).

[0087] Electro-optic element build: Using a razor blade, the outside perimeter of the anode and cathode films were removed to allow room for an epoxy seal. A thermally cured amineepoxy seal containing glass spacer beads was used to adhere the electrodes together leaving a small port hole. The part was filled with the electrolyte solution by vacuum backfilling. The port hole was filled with a UV-cured epoxy resin. Over time, the electrolyte gelled into a freestanding solid.

[0088] Electro-optic element test: Figure 14 shows a transmission plot of Example 7 under an applied voltage versus time. As illustrated, at 0V the element 7 is at 65% transmission (T), which drops to 4.2%T at 0.7V. Shorting element 7 caused it to bleach and return to a high transmission state.

[0089] Memory test: 0.7V was applied to element 7, which caused it to darken. Leaving the part at open circuit caused it to stay dark for greater than 20 minutes, thereby indicating a degree of memory for this construction. In examples where the electro-optic element 10 is built using different methods/procedures, memory can be improved. In this way, example 7 is merely illustrative of the ability for the electro-optic element 10 to include memory functionality. Open circuit current density can provide an indication of how quickly a part is clearing. Typically, a bi-stable device in a darkened state under an open circuit requires a current density that is lower (e.g., by a predetermined threshold, for example, 1 mA/cm²) than a solution-based element of similar size and color parameters. Accordingly, an electro-optic element that maintains a high optical density at a lower overall charge can be produced.

[0090] Example 8

[0091] Acid catalyzed transesterification of PSi29-b-PMAi353-b-PSi32 (PMA:PS of 5.2:1.0) with benzyl alcohol.

[0092] Procedure: An oven dried 25mL Schlenk was charged with 1 (120mg, 1.13mmol MA), benzyl alcohol (184mg, 1.7mmol) and p-toluenesulfonic acid (48mg, 0.3mmol) in lOmL of anhydrous toluene under nitrogen. The flask was fitted with an 8" long condenser with a vent needle halfway down the condenser. The flask was heated in a 120°C oil bath for 9.5 days after which it was cooled to RT and precipitated into 160mL of rapidly stirred methanol. Collected an off-white, rubbery solid by filtration, washed with lOOmL of methanol, then dried under vacuum at 40°C for 4 hours. ¹H-NMR showed methyl to benzyl acrylate conversion of 15%. FIG. 13 is a proton nuclear magnetic resonance plot (¹H-NMR) comparing the starting polymer, 1, versus the product of Example 8 (the benzyl acrylate polymer) in CDCh. Of note, a new peak at 5.08ppm was the methylene (-CHj-phenyl) of benzyl acrylate compared to the methyl (-0- C/-/3) of methyl acrylate at 3.66ppm.

[0093] Example 9

[0094] Spray casting films of the product of synthetic scheme 500, Example 4, followed by solvent annealing in toluene.

[0095] Procedure: Prepared a 5 wt. % solution of Example 4 (511mg) in toluene (9.71g). The polymer solution was bubbled with argon for 10 minutes then put on stir plate to fully dissolve. Filtered the solution through a 0.45pM PTFE syringe filter. Applied ImL of polymer solution to a 75mm x 75mm HW-ITO electrode using an airbrush with nitrogen carrier gas over several passes. Prepared a total of four electrodes, one of which was pre-scored into a 3x3 array of 25mm x 25mm squares. The films were very hazy. Dried the electrodes in a nitrogen cabinet overnight. Three 25mm x 25mm polymer coated slides were placed vertically in a sealed jar saturated with toluene vapor in argon for four hours after which the films were removed and dried under vacuum for two hours. The films transitioned from hazy to highly transparent.

[0096] Example 10

[0097] Testing the solubility of various polystyrene blocks in electrolyte solvent. The results of Example 10 are shown in Table 4, below.

[0098] Procedure: Several test samples were prepared by charging vials with lOOmg of polystyrene particles prepared by RAFT polymerization as in Example 1 resulting in the molecular weights listed in Table 1. 5.0 mL of propylene carbonate was added to each vial which was then heated to 50°C with stirring. Observations were made at 24 hours and 192 hours while the samples were hot and at 200 hours after cooling to room temperature. As can be seen in Table 4, below, only the shortest polystyrene block with a molecular weight of 5700 had some slight solubility in propylene carbonate at 50°C, which then precipitated and formed a cloudy solution upon cooling to room temperature. This indicates that the polystyrene blocks need length of > 5700 g/mol to adequately stabilize the polymer films in the presence of a propylene carbonate electrolyte solvent.

[0099] Table 4

[00100] Polymers according to aspects of the present disclosure provide a variety of benefits, especially when used in multilayer-based electrochromic devices. The polymers of the present disclosure can be readily purified prior to deposition such that all electroactive small molecule impurities are removed from the polymer such that device current leakage from these impurities are not a concern. Films for devices that are made using the polymers of the present disclosure can be deposited onto electrodes under ambient conditions without concern for humidity or moisture. Because these electrochromic polymers do not require additiona l/fu rther reaction (e.g., the polymers can self-assemble), the polymers of the present disclosure can form coating solutions that have the required physical properties (e.g., viscosity) to prepare uniform films. Further, the polymers can physically crosslink (rather than chemically crosslink) which reduces or eliminates the risk for premature crosslinking, use of reactive chemicals, use of extended curing times, and sensitivity to moisture. Additionally, devices that are made using the polymers of the present disclosure display rapid electroactivity and stability to loss of charge density.

[00101] According to one aspect of the present disclosure, an electro-optic sub-assembly includes a substrate which defines the first and second surfaces. An electrically conductive layer is disposed on the second surface. One of an anodic film and a cathodic film are disposed on the electrically conductive layer, wherein one of the anodic film and the cathodic film includes a plurality of tri-block copolymers. Each tri-block copolymer includes a first physical crosslinking block and a second physical crosslinking block that are insoluble with the electrolyte layer. A electrochromic block is covalently bonded between the first and second physical crosslinking block, wherein the electrochromic block is compatible with an electrolyte, and, wherein the first physical crosslinking blocks and the second physical crosslinking blocks of the plurality of tri-block copolymers aggregate with one another, such that one of an anodic film and a cathodic film is immobile on the electrically conductive layer.

[00102] According to another aspect of the present disclosure, a first tri-block copolymer unit is physically cross-linked with a second tri-block copolymer unit.

[00103] According to yet another aspect of the present disclosure, the plurality of tri-block copolymers are poly(styrene-b-substituted acrylates-b-styrene).

[00104] According to one aspect of the present disclosure, the block copolymer includes at least one block, which imparts a functionality including at least one of an increased processability, produces a UV-visible absorbance effect, or ionic charge.

[00105] According to another aspect of the present disclosure, the electrochromic block includes a repeat unit.

[00106] According to yet another aspect of the present disclosure, the physical crosslinking block includes a polystyrene block. [00107] According to another aspect of the present disclosure, the electrochromic block includes a polyacrylate block.

[00108] According to yet another aspect of the present disclosure, the physical crosslinking block aggregates with a second physical crosslinking block, thereby forming a physical crosslink.

[00109] According to another aspect of the present disclosure, an electro-optic element includes a first substrate defining first and second surfaces, wherein a first electrically conductive layer is disposed on the second surface. A second substrate defining third and fourth surfaces, wherein a second electrically conductive layer is disposed on the third surface. A medium is disposed between the second and third surfaces including a cathodic film disposed on a first electrically conductive layer, an anodic film disposed on a second electrically conductive layer, and an electrolyte layer between the cathodic film and the anodic film. The anodic film includes a tri-block copolymer including a first physical crosslinking block and a second physical crosslinking block that are insoluble with the electrolyte layer. An electrochromic block is covalently bonded between the first and second physical crosslinking block, wherein the electrochromic block is compatible with the electrolyte layer, wherein the tri-block copolymer is immobile on the second electrically conductive layer.

[00110] According to yet another aspect of the present disclosure, the tri-block copolymer is poly(styrene-b-substituted acrylates-b-styrene).

[00111] According to another aspect of the present disclosure, the first physical crosslinking block and the second physical crosslinking block aggregate, thereby forming a physical crosslink.

[00112] According to another aspect of the present disclosure, an electro-optic element includes a substrate that has an electrically conductive layer and one of an anodic film and a cathodic film. The electro-optic element also includes an electrolyte layer adjacent one of the cathodic and anodic films. One of the cathodic and anodic films has a block copolymer that includes a physical crosslinking block that is insoluble with the electrolyte layer and an electrochromic block covalently bonded to the physical crosslinking block. The electrochromic block is compatible with the electrolyte layer. [00113] According to still another aspect of the present disclosure, a block copolymer remains bonded to an electrically conductive layer during and after application of an electric potential to an electro-optic element.

[00114] It will be understood by one having ordinary skill in the art that construction of the described disclosure and other components is not limited to any specific material. Other exemplary embodiments of the disclosure disclosed herein may be formed from a wide variety of materials, unless described otherwise herein.

[00115] For purposes of this disclosure, the term "coupled" (in all of its forms, couple, coupling, coupled, etc.) generally means the joining of two components (chemical, electrical or mechanical) directly or indirectly to one another. Such joining may be stationary in nature or movable in nature. Such joining may be achieved with the two components (chemical, electrical or mechanical) and any additional intermediate members being integrally formed as a single unitary body with one another or with the two components. Such joining may be permanent in nature or may be removable or releasable in nature unless otherwise stated.

[00116] It is also important to note that the construction and arrangement of the elements of the disclosure, as shown in the exemplary embodiments, is illustrative only. Although only a few embodiments of the present innovations have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited. For example, elements shown as integrally formed may be constructed of multiple parts, or elements shown as multiple parts may be integrally formed, the operation of the interfaces may be reversed or otherwise varied, the length or width of the structures and/or members or connector or other elements of the system may be varied, the nature or number of adjustment positions provided between the elements may be varied. It should be noted that the elements and/or assemblies of the system may be constructed from any of a wide variety of materials that provide sufficient strength or durability, in any of a wide variety of colors, textures, and combinations. Accordingly, all such modifications are intended to be included within the scope of the present innovations. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the desired and other exemplary embodiments without departing from the spirit of the present innovations.

[00117] It will be understood that any described processes or steps within described processes may be combined with other disclosed processes or steps to form structures within the scope of the present disclosure. The exemplary structures and processes disclosed herein are for illustrative purposes and are not to be construed as limiting.

[00118] It is also to be understood that variations and modifications can be made on the aforementioned structures and methods without departing from the concepts of the present disclosure, and further it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise.

Claims

What is claimed is:

1. An electro-optic element, comprising: a cathodic film disposed on a first electrically conductive layer; an anodic film disposed on a second electrically conductive layer; and an electrolyte layer between the cathodic film and the anodic film, wherein one of the cathodic film and the anodic film comprise: a block copolymer comprising: a physical crosslinking block that is insoluble with the electrolyte layer; and an electrochromic block covalently bonded to the physical crosslinking block, wherein the electrochromic block is compatible with the electrolyte layer; and wherein the block copolymer is immobile on the corresponding one of the first electrically conductive layer and second electrically conductive layer.

2. The electro-optic element of claim 1, wherein the block copolymer includes at least one block, which imparts a functionality including at least one of an increased compatibility with an electrolyte, ionic conductivity, and/or electro-optical effects in a UV-Vis-NIR spectrum.

3. The electro-optic element of one of either one of claims 1 or 2, wherein the block copolymer remains bonded to one of the first electrically conductive layer and second electrically conductive layer during and after application of an electric potential to said electro-optic element.

4. The electro-optic element of any one of claims 1-3, wherein said electro-optic element is configured to remain in a current optical state under open circuit conditions for at least 10 minutes.

5. The electro-optic element of any one of claims 1-4, wherein the electrochromic block includes a repeat unit.

6. The electro-optic element of any one of claims 1-5, wherein the physical crosslinking block aggregates with physical crosslinking blocks on adjacent block copolymers, thereby forming a physical cross-link.

7. The electro-optic element of claim 2, wherein the electrochromic block is prepared by polymerization of functionalized monomers, the functionalized monomers including at least one of properties that increase compatibility with an electrolyte, increase ionic conductivity, and/or have electro-optical effects in the UV-Vis-NIR spectrum.

8. The electro-optic element of any one of claims 1-4, wherein the electrochromic block is prepared by post polymerization modification of block repeat units.

9. The electro-optic element claim 8, wherein the post polymerization modification includes transesterification of an acrylate repeat unit, thereby forming a block which imparts a functionality that is bonded to the polymer backbone via an ester bond.

10. The electro-optic element of claim 8, wherein the post polymerization modification includes amidation of an acrylate repeat unit, thereby forming a block which imparts a functionality that is bonded to the polymer backbone via an amide bond.

11. An electro-optic element, comprising: a substrate including an electrically conductive layer and one of an anodic film and a cathodic film; and an electrolyte layer adjacent one of the cathodic and anodic films, wherein one of the cathodic and anodic films comprises: a block copolymer comprising: a physical crosslinking block that is insoluble with the electrolyte layer; and an electrochromic block covalently bonded to the physical crosslinking block, wherein the electrochromic block is compatible with the electrolyte layer.

12. The electro-optic element of claim 11, wherein the electrochromic block includes a repeat unit.

13. The electro-optic element of either one of claims 11 or 12, wherein the physical crosslinking block aggregates with physical crosslinking blocks on adjacent block copolymers, thereby forming a physical cross-link.

14. The electro-optic element of any one of claims 11-13, wherein the electrochromic block is prepared by polymerization of functionalized monomers, the functionalized monomers including at least one of properties that increase compatibility with an electrolyte, increase ionic conductivity, and/or have electro-optical effects in a UV-Vis-NIR spectrum.

15. The electro-optic element of claim 11, wherein the electrochromic block is prepared by post polymerization modification of block repeat units.

16. The electro-optic element claim 15, wherein the post polymerization modification includes transesterification of an acrylate repeat unit, thereby forming a block which imparts a functionality that is bonded to the polymer backbone via an ester bond.

17. The electro-optic element of claim 15, wherein the post polymerization modification includes amidation of an acrylate repeat unit, thereby forming a block which imparts a functionality that is bonded to the polymer backbone via an amide bond.

18. The electro-optic element of claim 14, wherein the block copolymer includes at least one block, which imparts a functionality including at least one of an increased compatibility with an electrolyte, ionic conductivity, and/or electro-optical effects in the UV-Vis-NIR spectrum.

19. The electro-optic element of one of any one of claims 11-18, wherein the block copolymer remains bonded to the electrically conductive layer during and after application of an electric potential to said electro-optic element.

20. The electro-optic element of one of any one of claims 11-19, wherein said electro-optic element is configured to remain in a current optical state under open circuit conditions for at least 10 minutes.