阅读说明：本技术 具有透明离子交换膜的电光装置 (Electro-optical device with transparent ion exchange membrane ) 是由 Z·B·艾尔诺 L·J·克勒普纳 S·F·弗兰兹 J·C·内姆斯 G·C·德诺夫 N·P· 于 2018-08-08 设计创作，主要内容包括：提供了一种电致变色装置,其包括阴极隔室、阳极隔室和设置在阴极隔室与阳极隔室之间的透明离子选择性膜,其中,阴极隔室包含阴极材料,阳极隔室包含阳极材料,其中透明离子选择性膜为阳离子型聚合物。(An electrochromic device is provided comprising a cathode compartment, an anode compartment and a transparent ion-selective membrane disposed between the cathode compartment and the anode compartment, wherein the cathode compartment comprises a cathode material and the anode compartment comprises an anode material, wherein the transparent ion-selective membrane is a cationic polymer.)

1. A cationic polymer represented by formula I, formula II, or formula III:

wherein:

each R¹Independently alkylene, cycloalkylene, or heterocycloalkylene;

R²is H;

each R³May be individually absent, -O-or-alkyl-;

each R^3aMay be independently-alkyl-;

each R⁴Independently alkylene, cycloalkylene, or heterocycloalkylene;

each R⁵Independently absent, alkylene, cycloalkylene, or heterocycloalkylene;

each R⁶Individually absent or alkylene;

each R⁷Independently a group of the formula:

-[P(R¹³)₃]⁺or- [ N (R)¹¹)₃]⁺；

R⁸Is alkyl, cycloalkyl or heterocycloalkyl;

each R⁹Independently H, F, Br, Cl, NO₂Alkyl, cycloalkyl, alkoxy, aryl or heteroaryl, or any two of R alone⁹The groups may be joined together to form a ring which may be saturated or unsaturated;

each R¹⁰Independently H, F, Br, Cl, NO₂Alkyl, cycloalkyl, alkoxy, aryl or heteroaryl, or any two of R alone¹⁰The groups may be joined together to form a ring which may be saturated or unsaturated;

each R¹¹Independently H, alkyl, cycloalkyl, aryl or heteroaryl, or any two independent R¹¹The groups may be joined together to form a ring which may be saturated or unsaturated;

each R¹²May be independently H or alkyl;

each R¹²May be independently an alkyl or aryl group;

each Cat is a cationic group;

each X^-Individually, anionic;

each of n, p and r^1-5Indicating a repeating unit of the polymer;

each q may be independently 1, 2 or 3;

independently, T is independently absent, C (O) or CH₂(ii) a And is

Separately, T' is either absent or c (o) alone.

2. A cationic polymer according to claim 1, wherein:

each R¹Independently C₁-C₆Alkylene radical, C₃-C₁₆Cycloalkylene or C₃-C₁₆Heterocycloalkylene;

R²is H;

each R³Independently C₁-C₆Alkyl radical, C₃-C₁₆Cycloalkyl or C₃-C₁₆A heterocycloalkyl group;

each R⁴Independently C₁-C₆Alkylene radical, C₃-C₁₆Cycloalkylene or C₃-C₁₆Heterocycloalkylene;

each R⁵Independently absent, is C₁-C₆Alkylene radical, C₃-C₁₆Cycloalkylene or C₃-C₁₆Heterocycloalkylene;

each X^-Individually, anionic; and is

q is 2.

3. A cationic polymer according to claim 1, wherein the anion comprises F^-、Cl^-、Br^-、I^-、BF₄ ^-、PF₆ ^-、SbF₆ ^-、AsF₆ ^-、ClO₄ ^-、SO₃CF₃ ^-、N(CF₃SO₂)₂ ^-、C(CF₃SO₂)₃ ^-Triflate (trifluoromethanesulfonate), N (SO)₂C₂F₅)^-Or BAR₄ ^-Wherein Ar is an aryl or fluorinated aryl or bis (trifluoromethyl) aryl group.

4. A cationic polymer according to claim 1, wherein n is 10 to 100, p is 2 to 50, and r^1-5Each individually 25 to 5,000.

5. A cationic polymer according to claim 1, wherein R⁷Is composed of

6. A cationic polymer according to claim 1, wherein R⁷Is composed of

7. A cationic polymer according to claim 1, wherein "Cat" is one of:

wherein R is²⁰Is H, alkyl, cycloalkyl or heterocyclyl.

8. A cationic polymer of claim 1, represented by one or more of formulas IA-D or IIA-D:

wherein the parenthetical indications n, p and r in each of formulae IA-D and IIA-D^1-5The repeating unit of (1).

9. A cationic polymer according to claim 1, which is crosslinked with a crosslinking agent.

10. A cationic polymer according to claim 9, wherein the crosslinker is a diisocyanate, triisocyanate, polyisocyanate, or dialdehyde.

11. An electrochromic device, comprising:

a cathode compartment comprising a cathode material;

an anode compartment comprising an anode material; and

a transparent ion-selective membrane disposed between the cathode compartment and the anode compartment;

wherein:

the transparent ion-selective membrane comprises a cationic polymer.

12. The electrochromic device of claim 11, wherein the cationic polymer comprises an ammonium, pyridinium, imidazolium, or phosphonium functionality; and an oxygen containing backbone.

13. The electrochromic device of claim 11, wherein the cationic polymer is represented by formula I, formula II, or formula III:

wherein:

each R¹Independently alkylene, cycloalkylene, or heterocycloalkylene;

R²is H;

each R³Independently alkyl, cycloalkyl or heterocycloalkyl;

each R⁴Independently alkylene, cycloalkylene, or heterocycloalkylene;

each R⁵Independently absent, alkylene, cycloalkylene, or heterocycloalkylene;

each R⁶Do not exist aloneAt or as an alkylene group;

each R¹²Is H;

each R⁷Independently of formula

each X^-Individually, anionic;

each of n, p and r^1-5Indicating a repeating unit of the polymer;

each q may be independently 1, 2 or 3;

independently, T is independently absent, C (O) or CH₂(ii) a And is

Separately, T' is either absent or c (o) alone.

14. The electrochromic device of claim 13, wherein:

each R¹Independently C₁-C₆Alkylene radical, C₃-C₁₆Cycloalkylene or C₃-C₁₆Heterocycloalkylene;

R²is H;

each R³Independently C₁-C₆Alkyl radical, C₃-C₁₆Cycloalkyl or C₃-C₁₆A heterocycloalkyl group;

each R⁴Independently C₁-C₆Alkylene radical, C₃-C₁₆Cycloalkylene or C₃-C₁₆Heterocycloalkylene;

each R⁵Independently absent or as C₁-C₆Alkylene radical, C₃-C₁₆Cycloalkylene or C₃-C₁₆Heterocycloalkylene;

each X^-Individually, anionic; and is

q is 2.

15. The electrochromic device of claim 13, wherein the anion comprises F^-、Cl^-、Br^-、I^-、BF₄ ^-、PF₆ ^-、SbF₆ ^-、AsF₆ ^-、ClO₄ ^-、SO₃CF₃ ^-、N(CF₃SO₂)₂ ^-、C(CF₃SO₂)₃ ^-Triflate (trifluoromethanesulfonate), N (SO)₂C₂F₅)^-Or BAR₄ ^-Wherein Ar is an aryl or fluorinated aryl or bis (trifluoromethyl) aryl group.

16. The electrochromic device of claim 13, wherein n is 10 to 100, p is 2 to 50, and r^1-5Each individually 25 to 5,000.

17. The electrochromic device of claim 13, wherein R⁷Is composed of

18. The electrochromic device of claim 13, wherein R⁷Is composed of

19. The electrochromic device of any one of claims 13-15, wherein the cationic polymer is represented by one or more of formulas IA-D or IIA-D:

wherein the parenthetical indications n, p and r in each of formulae IA-D and IIA-D^1-5The repeating unit of (1).

20. The electrochromic device of claim 11, wherein the cathode material comprises viologen.

21. The electrochromic device of claim 11, wherein the anode material comprises a phenazine, phenothiazine, triphenoldithiazine, carbazole, indolocarbazole, biscarbazole, or ferrocene.

22. The electrochromic device of claim 11, further comprising an electrolyte.

23. The electrochromic device of claim 22, wherein the electrolyte comprises a solvent and a metal or ammonium salt.

24. The electrochromic device of claim 11 or 13, wherein the cationic polymer is crosslinked with a crosslinking agent.

25. The electrochromic device of claim 24, wherein the crosslinker is a diisocyanate, triisocyanate, polyisocyanate, or dialdehyde.

26. The electrochromic device of claim 11, wherein the cationic polymer comprises a pyridinium-functional and oxygen-containing backbone.

27. The electrochromic device of claim 11, wherein the cationic polymer comprises an imidazolium-functional and oxygen-containing backbone.

28. An electrochromic device, comprising:

a cathode compartment comprising viologen;

an anode compartment comprising a metallocene, a 5, 10-dihydrophenazine, a phenothiazine, a phenoxazine, a carbazole, a triphenoldioxazine, or a triphenoldithiazine; and

a transparent ion-selective membrane disposed between the cathode compartment and the anode compartment;

wherein:

the transparent ion-selective membrane comprises an anionic or cationic polymer.

29. The electrochromic device of claim 28, wherein the transparent ion-selective membrane comprises an anionic polymer and one or both of the cathode and anode materials are anionic in an activated state.

30. The electrochromic device of claim 28, wherein the transparent ion-selective membrane comprises a cationic polymer and one or both of the cathode and anode materials are cationic in an activated state.

Technical Field

The present technology relates generally to electro-optic devices. More particularly, the present technology relates to electrochromic devices that once charged have a persistent color memory for a significant period of time after the voltage is removed. The present technology also relates to polymeric materials and ion exchange or ion selective membranes.

Disclosure of Invention

In one aspect, a cationic polymer is provided as represented by formula I, formula II, or formula III:

in the above formula:

each R¹May be independently alkylene, cycloalkylene, or heterocycloalkylene;

R²can be H;

each R³May be individually absent, -O-or-alkyl-;

each R^3aMay be independently-alkyl-;

each R⁴May be independently alkylene, cycloalkylene, or heterocycloalkylene;

each R⁵May be individually absent or alkylene, cycloalkylene or heterocycloalkylene;

each R⁶May be absent or alkylene, individually;

each R⁷May be independently a group of the formula:

-[P(R¹³)₃]⁺or- [ N (R)¹¹)₃]⁺；

R⁸May be independently alkyl, cycloalkyl or heterocycloalkyl;

each R⁹Can be independently H, F, Br, Cl, NO₂Alkyl, cycloalkyl, alkoxy, aryl or heteroaryl, or any two of R alone⁹The groups may be joined together to form a ring which may be saturated or unsaturated;

each R¹⁰Can be independently H, F, Br, Cl, NO₂Alkyl, cycloalkyl, alkoxy, aryl or heteroaryl, or any two of R alone¹⁰The groups may be joined together to form a ring which may be saturated or unsaturated;

each R¹¹May be independently alkyl, cycloalkyl, aryl or heteroaryl, or any two of R alone¹¹The groups may be joined together to form a ring which may be saturated or unsaturated;

each R¹²May be independently H or alkyl;

each R¹³May be independently an alkyl or aryl group;

each Cat is a cationic group;

each X^-May be solely anionic;

each of n, p and r^1-5A repeat unit of an indicator polymer;

each q may be independently 1, 2 or 3;

each T can be independentlyIs absent, is C (O) or CH₂(ii) a And

each T' may be independently absent or c (o).

In some embodiments of the above formula, each R¹May be independently C₁-C₆Alkylene radical, C₃-C₁₆Cycloalkylene or C₃-C₁₆Heterocycloalkylene; r²Can be H; each R³May be independently C₁-C₆Alkyl radical, C₃-C₁₆Cycloalkyl or C₃-C₁₆A heterocycloalkyl group; each R⁴May be independently C₁-C₆Alkylene radical, C₃-C₁₆Cycloalkylene or C₃-C₁₆Heterocycloalkylene; each R⁵May be absent or C alone₁-C₆Alkylene radical, C₃-C₁₆Cycloalkylene or C₃-C₁₆Heterocycloalkylene; each X^-May be solely anionic; and q is 2.

In some embodiments of the above formula, each Cat can be a cationic cyclic group, a cationic heterocyclyl group, a cationic aryl group, or a cationic heteroaryl group. Exemplary Cat groups include a linkage to R at the 1 (i.e., nitrogen position), 2,3, 4, 5, or 6 position of the pyridinium ring³(or attached to an acetal group if R³Absent) pyridinium group, to R at position 1, 2,3, 4 or 5 of the imidazolium ring³(or attached to an acetal group if R³Absent) imidazolium groups, or a benzene ring with a phosphonium or ammonium substituent. In some embodiments, the Cat group is a group that is one of:

wherein R is²⁰Is H, alkyl, cycloalkyl or heterocyclyl. In some embodiments, the Cat group is:

wherein R is²⁰Is H, alkyl, cycloalkyl or heterocyclyl. In some embodiments, R³Absent and the Cat group is a group that is one of:

wherein R is²⁰Is H, alkyl, cycloalkyl or heterocyclyl. In some embodiments, R³Absent and Cat groups are:

wherein R is²⁰Is H, alkyl, cycloalkyl or heterocyclyl.

In any embodiment of the above formula, R⁶Can be-CH₂-. In any embodiment of the above formula, R^3aCan be-CH₂-、–CH₂CH₂-、–CH₂CH₂CH₂-、–CH₂CH₂CH₂CH₂-、–CH₂CH₂CH₂CH₂CH₂-or-CH₂CH₂CH₂CH₂CH₂CH₂-。

In another aspect, an electrochromic device includes a cathode compartment comprising a cathode material; an anode compartment comprising an anode material; and a transparent ion-selective membrane disposed between the cathode compartment and the anode compartment; wherein the transparent ion-selective membrane comprises a cationic polymer. In some embodiments of the device, the cationic polymer comprises an ammonium, phosphonium, pyridinium, or imidazolium functionality; and an oxygen containing backbone. In some embodiments, the electrochromic device comprises any one of the cationic polymers described by any one or more of formula I, formula II, or formula III herein. In some embodiments, the transparent ion-selective membrane comprises an anionic polymer and one or both of the cathode and anode materials are anions in an activated state. In other embodiments, the transparent ion-selective membrane comprises a cationic polymer and one or both of the cathode and anode materials are cations in an activated state.

Drawings

Fig. 1 is a cross-sectional view of an electrochromic device according to one embodiment.

FIG. 2 is a diagram of a layering process for forming an electrochromic device, according to one embodiment.

Fig. 3 is a schematic view of a first alternative layered structure for an electrochromic device according to one embodiment.

Fig. 4 is a schematic view of a second alternative layered structure for an electrochromic device according to one embodiment.

Detailed Description

Various embodiments are described below. It should be noted that the specific embodiments are not intended as an exhaustive description or as a limitation on the broader aspects discussed herein. An aspect described in connection with a particular embodiment is not necessarily limited to that embodiment, but may be practiced with any other embodiment or embodiments.

As used herein, "about" will be understood by one of ordinary skill in the art and will vary to some extent depending on the context in which it is used. If the use of this term is not clear to one of ordinary skill in the art, then in view of its context of use, "about" will mean at most plus 10% or minus 10% of this particular term.

The use of the terms "a" and "an" and "the" and similar referents in the context of describing elements (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. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly 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 embodiments and does not pose a limitation on the scope of the claims unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential.

Generally, "substituted" refers to an alkyl, alkenyl, alkynyl, aryl, or ether group (e.g., an alkyl group) as defined below in which one or more of the bonds contained therein to a hydrogen atom is replaced with a bond to a non-hydrogen or non-carbon atom. Substituted groups also include groups in which one or more carbon or hydrogen atom bonds are replaced by one or more heteroatomic bonds, including double or triple bonds. Thus, unless otherwise specified, a substituted group will be substituted with one or more substituents. In some embodiments, a substituted group is substituted with 1, 2,3, 4, 5, or 6 substituents. Examples of the substituent include: halogen (i.e., F, Cl, Br, and I); a hydroxyl group; alkoxy, alkenyloxy, alkynyloxy, aryloxy, aralkyloxy, heterocyclyloxy, and heterocyclylalkoxy; carbonyl (oxo); a carboxyl group; an ester; a carbamate; an oxime; a hydroxylamine; an alkoxyamine; an arylalkoxyamine; a thiol; a thioether; a sulfoxide; a sulfone; a sulfonyl group; a sulfonamide; an amine; an N-oxide; hydrazine; a hydrazide; hydrazone; an azide; an amide; urea; amidines; guanidine; an enamine; an imide; an isocyanate; an isothiocyanate; a cyanate ester; a thiocyanate; an imine; a nitro group; nitriles (i.e., CN), and the like.

As used herein, "alkyl" groups include straight and branched alkyl groups having from 1 to about 20 carbon atoms and typically from 1 to 12 carbons or, in some embodiments, from 1 to 8 carbon atoms. As used herein, "alkyl" includes cycloalkyl as defined below. The alkyl group may be substituted or unsubstituted. Examples of straight chain alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, and n-octyl. Examples of branched alkyl radicals include, but are not limited to, isopropyl, sec-butyl, tert-butyl, neopentyl, and isopentyl. Representative substituted alkyl groups can be substituted one or more times with, for example, amino, thio, hydroxy, cyano, alkoxy, and/or halo (e.g., F, Cl, Br, and I groups). As used herein, the term haloalkyl is an alkyl having one or more halo groups. In some embodiments, haloalkyl refers to a perhaloalkyl group.

Cycloalkyl groups are cyclic alkyl groups such as, but not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. In some embodiments, cycloalkyl groups have 3 to 8 ring members, while in other embodiments the number of ring carbon atoms ranges from 3 to 5, 6, or 7. Cycloalkyl groups may be substituted or unsubstituted. Cycloalkyl groups further include polycyclic cycloalkyl groups such as, but not limited to, norbornyl, adamantyl, bornyl, camphene, isobornenyl, and carenyl, and fused rings such as, but not limited to, decahydronaphthyl and the like. Cycloalkyl also includes rings substituted with straight or branched chain alkyl as defined above. Representative substituted cycloalkyl groups may be mono-substituted or substituted more than once, such as but not limited to: 2,2-, 2,3-, 2,4-, 2, 5-or 2, 6-disubstituted cyclohexyl radicals or mono-, di-or tri-substituted norbornyl or cycloheptyl radicals, which radicals may be substituted, for example, by alkyl, alkoxy, amino, thio, hydroxy, cyano and/or halogen radicals.

An alkenyl group is a straight, branched, or cyclic alkyl group having 2 to about 20 carbon atoms and further including at least one double bond. In some embodiments, alkenyl groups have 2 to 12 carbons or typically 2 to 8 carbon atoms. The alkenyl group may be substituted or unsubstituted. Alkenyl includes, for example, ethenyl, propenyl, 2-butenyl, 3-butenyl, isobutenyl, cyclohexenyl, cyclopentenyl, cyclohexadienyl, butadienyl, pentadienyl and hexadienyl, among others. Alkenyl groups may be substituted similarly to alkyl groups. Divalent alkenyl groups (i.e., alkenyl groups having two points of attachment) include, but are not limited to, CH-CH ═ CH₂、C＝CH₂Or C ═ CHCH₃。

As used herein, an "aryl" or "aromatic" group is a cyclic aromatic hydrocarbon free of heteroatoms. Aryl groups include monocyclic, bicyclic, and polycyclic ring systems. Thus, aryl groups include, but are not limited to, phenyl, azulenyl, heptenylene, biphenylene, dicyclopentadiene acenyl (indacenyl), fluorenyl, phenanthrenyl, triphenylenyl (triphenylenyl), pyrenyl, naphthacenyl (naphthacenyl), chrysenyl (chrysenyl), biphenyl, anthracenyl, indenyl, indanyl, pentalenyl, and naphthyl. In some embodiments, the cyclic portion of the aryl group contains from 6 to 14 carbons, and in other embodiments, from 6 to 12 or even from 6 to 10 carbon atoms. The term "aryl" includes groups containing fused rings, such as fused aromatic-aliphatic ring systems (e.g., indanyl, tetrahydronaphthyl, and the like). The aryl group may be substituted or unsubstituted.

Unless otherwise specifically stated, reference to any group such as alkyl, aryl, heteroaryl, heterocyclyl, cyclyl, alkenyl, alkynyl and the like includes reference to such groups as substituted and unsubstituted.

One of the advantages of solution-based electrochromic devices is that they are very stable to chemical durability tests (weatherability). However, one disadvantage of single compartment, self-erasing, solution-based electrochromic devices, at least for some applications, is the need to apply constant power to the device to keep it in a dark state. Constant power consumption makes some applications difficult to implement or prohibitively expensive. A multi-compartment device is provided herein that is capable of maintaining a dark state or a low transmittance state at open circuit. The multi-compartment device comprises a cathode compartment and an anode compartment with a separator layer in between. In addition, the separator layer comprises a colorless or at least nearly colorless, transparent, chemically stable ion exchange membrane. Such a membrane allows electrolyte of a particular charge to diffuse freely through the membrane, but prohibits (or at least significantly hinders) free passage of the opposite charge. For example, if the membrane is a cationic membrane, it will allow anions to pass through while rejecting cations, and vice versa. Thus, when the device is in an electrochemically active and/or dark state, it will allow the passage of ions of one charged type while blocking the passage of oppositely charged ions.

In the devices described herein, the anode and cathode redox-active materials should be soluble ionic compounds of the same charge (i.e., negative or positive), while in the electrochemically active and/or dark state, the membrane separating the redox-active media should only allow passage of the opposite charge from the supporting electrolyte or counter-ion associated with the electrochromic material. For example, if the cathode and/or anode materials are positively charged in both the active and/or dark state, the ion exchange membrane should be an anion exchange membrane. Alternatively, if both the cathode and anode materials are negatively charged in the active and/or dark state, the ion exchange membrane should be a cation exchange membrane. The electrolyte of opposite charge to the membrane may be derived from the supporting electrolyte and/or be a counter ion from the redox electroactive anode or cathode material. Once the device is subjected to a charging event and the device reaches a low transmittance state, the device should remain in the low transmittance state and not be self-erasing for a specified period of time. The device allows no or very low power consumption, whether with an applied potential or at open circuit, while maintaining the electrochromic device in its low transmittance state. Electrochromic device applications such as architectural windows, skylights, and wearable devices such as, but not limited to, sunglasses or augmented reality glasses all require reduced power consumption. In addition, reduced power would mean reduced current draw, resulting in a reduced "iris" effect — this can be noted in a self-erasing device where the outer edges of the device darken significantly before the center of the device.

In one aspect, an electrochromic device includes a cathode compartment, an anode compartment, and a transparent ion-selective membrane disposed between the cathode compartment and the anode compartment. The anode compartment contains an anode redox active material and the cathode compartment contains a cathode redox active material. The transparent ion-selective membrane may comprise a cationic polymer or an anionic polymer. In some embodiments, the transparent ion-selective membrane comprises a cationic polymer. In some embodiments, the transparent ion-selective membrane comprises an anionic polymer. In some embodiments, the transparent ion-selective membrane is covalently crosslinked to improve mechanical stability. With respect to a specified time period that the device should be able to maintain a low transmission state at open circuit, exemplary times include less than a 5% increase in transmission over at least 8 hours, or in some embodiments, less than a 5% increase in transmission over at least 24 hours. As used herein, transmittance is not measured at a single wavelength, but is measured as the total transmittance over the entire visible spectrum. As described above, once the device is subjected to a charging event and the device reaches a low transmittance state, the device should remain in the low transmittance state and not be self-erasing for a specified period of time.

In some embodiments, the transparent ion-selective membrane is an anionic polymer. For example, the anionic polymer may comprise Nafion (sulfonated tetrafluoroethylene). Strongly acidic Nafion can be treated with a base such as lithium hydroxide to form polyanionic Li⁺Sulfonate Nafion-Li⁺。Nafion-Li⁺Capable of conducting small cations but also capable of blocking anionic compounds, including negatively charged anodic or cathodic redox active materials.

In some embodiments, the transparent ion-selective membrane is a cationic polymer having an ammonium, pyridinium, phosphonium, or imidazolium functionality and an oxygen-containing backbone (i.e., a polymeric backbone having oxygen atoms in the backbone or a portion of the cyclic structure within the backbone). The cationic polymer may also be crosslinked using a crosslinking agent. Illustrative cationic polymers include, but are not limited to, those represented by formula I, formula II, or formula III:

in the above formula, each R¹Independently alkylene, cycloalkylene, or heterocycloalkylene; r²Is H; each R³Independently absent, -O-or-alkyl-; each R^3aIndependently-alkyl-; each R⁴Independently alkylene, cycloalkylene, or heterocycloalkylene; each R⁵Independently absent, alkylene, cycloalkylene, or heterocycloalkylene; each R⁶Individually absent or alkylene; each R⁷Independently of the formula [ P (R) ]¹³)₃]⁺、-[N(R¹¹)₃]⁺、

A group of (a); each Cat is a cationic group; each X^-Individually, anionic; each of n, p and r^1-5A repeat unit of an indicator polymer; each q is independently 1, 2 or 3; independently, T is independently absent, is C (O) or is CH₂；R⁸Is alkyl, cycloalkyl or heterocycloalkyl; each R⁹Independently H, F, Br, Cl, NO₂Alkyl, cycloalkyl, alkoxy, aryl or heteroaryl, or any two of R alone⁹The groups may be joined together to form a saturated or unsaturated ring, including with the attachment of R⁹A pyridine ring fused non-aryl or aryl ring of the group; each R¹⁰Independently H, F, Br, Cl, NO₂Alkyl, cycloalkyl, alkoxy, aryl or heteroaryl, or any two of R alone¹⁰The groups may be joined together to form a saturated or unsaturated ring, including with the attachment of R¹⁰A pyridine ring fused non-aryl or aryl ring of the group; each R¹¹Independently an alkyl, cycloalkyl, aryl or heteroaryl group, or any two independent R¹¹The groups may be joined together to form a ring which may be saturated or unsaturated; each R¹²Can be H or alkyl, each R¹³Is independently alkyl or aryl, preferably aryl, more preferably phenyl, and each T' is independently absent or is c (o). It is understood that the repeating units identified by brackets are merely a closed representation of an indefinite number of repeating units spaced throughout the polymer. Although it is not necessary to state that the polymer is precisely what this particular value is, it is necessary to say that n, p and r are^1-5Can be 10 to 100 for n, 2 to 50 for p, and r^1-5Each of which is 25 to 5,000. In some embodiments, this includes 10 to 60 for n, 4 to 20 for p, and r^1-5From 1,300 to 3,200 each, individually.

As will be noted, except on the polymerIn addition to the other potential substituents of (1), R⁷The groups also provide at least one site for introducing cationic moieties (i.e., "residues") in the polymer. The cationic residue can be about 10 mole% to about 50 mole% based on the repeating unit designated by p. This may include about 10 mole% to about 40 mole%; about 10 molar% to about 35 molar%; about 10 molar% to about 30 molar%; about 15 molar% to about 50 molar%; about 15 molar% to about 40 molar%; about 15 molar% to about 35 molar%; or from about 15 mol% to about 35 mol%. In some embodiments, the cationic residue can be from about 15 mole% to about 35 mole% of the polymer. In any of the above embodiments, each R is⁷Can be

Alternatively, in any of the above embodiments, each R is⁷Can be

For illustrative purposes, these cations are attached to the polymer backbone through a nitrogen atom on the cationic ring. It is also contemplated that the cationic ring may pass through R on the ring⁹And R¹⁰The group is covalently bound to the organic cation. In some embodiments, each R is⁷Is- [ P (R)¹³)₃]⁺Wherein R is¹³Is an aryl group, in some embodiments a phenyl group. In some embodiments, each R is⁷Is- [ N (R)¹¹)₃]⁺Wherein R is¹¹Is C₁-C₈An alkyl group.

In any of the above embodiments with respect to formulas I and II, each R¹May be independently C₁-C₆Alkylene radical, C₃-C₁₆Cycloalkylene or C₃-C₁₆Heterocycloalkylene; each R³May be independently C₁-C₆Alkyl radical, C₃-C₁₆Cycloalkyl or C₃-C₁₆A heterocycloalkyl group; each R⁴May be independently C₁-C₆Alkylene radical, C₃-C₁₆Cycloalkylene or C₃-C₁₆SuterocyclesAn alkyl group; each R⁵May be absent or C alone₁-C₆Alkylene radical, C₃-C₁₆Cycloalkylene or C₃-C₁₆Heterocycloalkylene; each X^-May be solely anionic. Illustrative examples of anions include, but are not limited to, F^-、Cl^-、Br^-、I^-、BF₄ ^-、PF₆ ^-、SbF₆ ^-、AsF₆ ^-、ClO₄ ^-、SO₃CF₃ ^-、N(CF₃SO₂)₂ ^-、C(CF₃SO₂)₃ ^-Triflate (trifluoromethanesulfonate), N (SO)₂C₂F₅)^-、BAr₄ ^-And mixtures of any two or more such anions, wherein Ar is an aryl or fluorinated aryl or a bis (trifluoromethyl) aryl group.

In some embodiments of the above formula, each Cat can be a cationic cyclic group, a cationic heterocyclyl group, a cationic aryl group, or a cationic heteroaryl group. Exemplary Cat groups include a linkage to R at the 1 (i.e., nitrogen position), 2,3, 4, 5, or 6 position of the pyridinium ring³(or attached to an acetal group if R³Absent) pyridinium group, to R at position 1, 2,3, 4 or 5 of the imidazolium ring³(or attached to an acetal group if R³Absent) imidazolium groups, or a benzene ring with a phosphonium or ammonium substituent. In some embodiments, the Cat group is a group that is one of:

wherein R is²⁰Is H, alkyl, cycloalkyl or heterocyclyl. In some embodiments, the Cat group is:

wherein R is²⁰Is H, alkyl, cycloalkyl or heterocyclyl. In some embodiments, R³Absent and the Cat group is a group that is one of:

wherein R is²⁰Is H, alkyl, cycloalkyl or heterocyclyl. In some embodiments, R³Absent and Cat groups are:

wherein R is²⁰Is H, alkyl, cycloalkyl or heterocyclyl.

In any embodiment of the above formula, R⁶Can be-CH₂-. In any embodiment of the above formula, R^3aCan be-CH₂-、–CH₂CH₂-、–CH₂CH₂CH₂-、–CH₂CH₂CH₂CH₂-、–CH₂CH₂CH₂CH₂CH₂-or-CH₂CH₂CH₂CH₂CH₂CH₂-。

Illustrative compounds according to formulas I, II and III include, but are not limited to, those of formulas IA-D, IIA-D and IIIA:

in formulas IA-D, IIA-D and IIIA, and as described above, the brackets indicate the repeating units of the polymer. Where specific values are required, they have been stated above.

As described above, the cationic polymer of the transparent ion-selective membranes described herein can be further crosslinked with a crosslinking agent. Illustrative crosslinking agents can include, but are not limited to, di-, tri-, and polyisocyanates. The dioxane bond depicted in formula IIIA is an acetal formed by the acid catalyzed reaction of adjacent hydroxyl groups on the polymer backbone with a dialdehyde crosslinking reagent (glutaraldehyde in the case of formula IIIA). Other acetal crosslinks may be similarly formed.

The transparent ion-selective membranes described herein with respect to polycaprolactone-based polymers (i.e., as shown by those having alkyl esters in the backbone, see, e.g., formulas IB, ID, IIB, and IID) can have a number average molecular weight of about 10,000 to about 250,000 daltons. This includes, but is not limited to, an illustrative range such as about 50,000 to about 180,000 daltons; about 50,000 to about 160,000 daltons; or from about 80,000 to about 160,000 daltons. Transparent ion-selective membranes described herein with respect to polyether polyols (i.e., as shown by those having alkyl esters in the backbone, see, for example, formulas IA, IC, IIA, and IIC) can have a number average molecular weight of from about 500 to about 20,000 daltons. These include, but are not limited to, illustrative ranges such as from about 1,000 to about 12,000 daltons; about 1,000 to about 8,000 daltons; or from about 1,400 to about 8,000 daltons.

Referring to fig. 1, an electrochromic device 100 is described herein. The apparatus 100 includes at least one cathode chamber 110 and at least one anode chamber 115. The cathode chamber 110 is defined by a first substrate 135 having a conductive surface 136 and an outer surface 137 and the cathode face 121 of the separator layer 120. The anode chamber 115 is defined by a second substrate 140 having a conductive surface 141 and an outer surface 142, and an anode face 122 of a separator layer 120, which is a transparent ion selective membrane. The conductive surface 136 of the first substrate 135 is joined to the conductive surface 141 of the second substrate 140 by a sealing member 125 (although clearly separated in the drawings, the seal is an integral element at the periphery of the device and the chamber).

The cathode and anode materials may be in solution phase or gel phase within the chambers 110, 115; the cathodic material may be confined to the conductive surface 136 while the anodic material is either in solution or confined to the conductive surface 141; or the anode material may be confined to the conductive surface 141 while the cathode material is either in solution or confined to the conductive surface 136. Electrolyte is disposed within chambers 110, 115 and within separator layer 120. The electrolyte may include anode and/or cathode materials. The first substrate 135 and the second substrate 140 may be biased relative to each other to allow electrical contact to their respective conductive surfaces 136, 141, as is recognized for other solution phase electrochromic devices.

Figure 2 illustrates a method of constructing a device. As shown in fig. 2, the device may be constructed from a first substrate 210 and a second substrate 270 separated by an ion exchange membrane 240. Both the first substrate 210 and the second substrate 270 are coated with a conductive layer on the side facing the other substrate. The anode and cathode chambers are formed by the substrates 210, 270 and the ion exchange membrane 240 separated by spacers 220, 250. The ion exchange membrane 240 must be strongly bonded to the gaskets 220, 250 to withstand the pressure differential during the vacuum assisted backfilling process. The fill ports 230, 260 provide conduits to fill the individual chambers with anode/cathode media under vacuum assisted backfill. After backfilling the chamber with anode and cathode media, the fill ports were sealed. An adhesive material such as epoxy resin may be used to bond the first substrate 210 and the first gasket 220, the gasket 220 and the first surface of the ion exchange membrane 240, the second surface of the ion exchange membrane 240 and the second gasket 250, and the second gasket 250 and the second substrate 270. Alternatively, the sizing of the gasket and ion exchange membrane may be such that the first substrate is bonded directly to the second substrate, but the bonding adhesive bonds and/or abuts the outer edge of the gasket such that each chamber is sealed, but only a single layer of laminating adhesive is observed from the outer edge of the device. The substrate may be made of glass or plastic. The gasket may likewise be made of glass, plastic, rubber, etc. The only limitation of the substrate and the shim is that the materials from which they are constructed should be compatible with the electrochromic medium and the adhesive material.

Referring to fig. 3 and 4, an alternative structural representation of an electrochromic device is depicted. In fig. 3, electrochromic device 300 is formed from layered anode gel 310 and cathode gel 330, separated by separator layer 320, which is a transparent ion-selective membrane. Below and above this stack are substrates 360, 361 with conductive layers 350, 351 and bus bar connectors 340, 341. The material of the substrate may be, for example, but not limited to, polyethylene terephthalate (PET); the material of the conductive layer may be, for example, but not limited to, indium tin oxide; the bus bars may be made of a conductive material such as a metal (i.e., copper, stainless steel, silver, gold, iron, or other metal, an alloy of any two or more thereof, or a blend of any two or more thereof). Fig. 4 illustrates an apparatus 400 comprising an apparatus 300 between further substrates 410 with barrier seals 420, 421 therebetween. Additionally, the chamber formed by the additional substrate 410 and barrier seals 420, 421 may optionally be a fluid, clear adhesive or laminate 430. The additional substrate may be a material such as glass and the adhesive may be an epoxy or other adhesive clear material or laminate such as, but not limited to, Ethylene Vinyl Acetate (EVA) and polyvinyl butyral (PVB).

In any of the above aspects, the cathode material can be a viologen, a hypodimeric viologen, a non-dimeric viologen, or a metal oxide such as tungsten oxide, as these terms are used in the art. The term hypodimeric viologen applies to some viologens that exhibit a less dimeric character than dimeric viologen. Illustrative viologens include, but are not limited to, methyl viologen, octyl viologen, benzyl viologen, and polymeric viologens. In addition, more viologens are described in U.S. Pat. Nos. 4,902,108, 6,188,505, 5,998,617 and 6,710,906 and U.S. patent application publication No. 2015/0346573.

In any of the above aspects, the anode material may include, but is not limited to, metallocenes, 5, 10-dihydrophenazines, phenothiazines, phenoxazines, carbazoles, triphenoldioxazines, triphenoldithiazines, and related compounds the anode material included in the electrochromic medium may include any of a variety of materials including ferrocene, substituted ferrocenyl salts, phenazines, substituted phenazines, phenothiazines, substituted phenothiazines (including substituted dithiazines), thianthrenes, and substituted thianthrenes, examples of anode materials may include di-tert-butyl-diethylferrocene, 5, 10-dimethyl-5, 10-Dihydrophenazines (DMP), bis (triethylaminopropyl) dihydrophenazines bis (tetrafluoroborate), 3,7, 10-trimethylphenothiazines, 2,3,7, 8-tetramethoxy-phenothiazines, 10-methylphenothiazines, Tetramethylphenazines (TMP), and bis (butyltriethylammoniumsl) -p-methoxy-triphenothiazines (DT), anode materials (TPT) may include a polymer, such as a polymer, a polymeric material including at least one of a metallocene, phenothiazine, phenoxazine, and related compounds including, phenoxazine, and related compounds including, and related compounds that when used in a substituted phenoxazine, and related compounds that when substituted, and when used in a substituted, an anode material, and when an electrochromic medium includes, and when a substituted with at least one of an anode material, such as described in a substituted, and when a substituted, at least one embodiment, an electrochromic medium, an embodiment, an electrochromic medium includes, an electrochromic medium includes, an embodiment, including at least one of an electrochromic medium includes, including at least one of the group, including at least one of the group, at least one of an embodiment, including at least one of the group, at least one.

In some embodiments, the solvent of the electrochromic medium may include, but is not limited to, 3-methyl sulfolane, dimethyl sulfoxide, dimethylformamide, tetraethylene glycol dimethyl ether 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 β -propiolactone, gamma-butyrolactone, gamma-valerolactone, Propylene Carbonate (PC), ethylene carbonate, oligoethers, and homogeneous mixtures of any two or more such solvents.

The salt may be a metal salt or an ammonium salt. Illustrative salts include, but are not limited to, metal or ammonium salts of anions such as, but not limited to, Li⁺、Na⁺、K⁺、NR’₄ ⁺Wherein each R' is independently H, alkyl or cycloalkyl, and the anion is F^-、Cl^-、Br^-、I^-、BF₄ ^-、PF₆ ^-、SbF₆ ^-、AsF₆ ^-、ClO₄ ^-、SO₃CF₃ ^-、N(CF₃SO₂)₂ ^-、C(CF₃SO₂)₃ ^-、N(SO₂C₂F₅)^-、Al(OC(CF₃)₃)₄ ^-Or BAR₄ ^-Wherein Ar is aryl or a fluorine-containing aryl group, such as (but not limited to) C₆H₅、3,5-(CF₃)₂C₆H₃]₄Or C₆F₅。

The electrochromic devices described herein exhibit a high transmittance state when shorted and a low transmittance state after an applied potential. In some embodiments, wherein the high transmittance state is at least 5 times higher than the low transmittance state; and the electrochromic device is configured to maintain the percent transmittance within 5% of the low transmittance state for at least 8 hours at open circuit after application of a potential sufficient to reach the low transmittance state. For the device, the low transmittance state may range from about 0.001% to about 30% transmittance, while the high transmittance state may be from about 50% to about 95% transmittance. In some embodiments, the high transmittance value does not change by more than 5% from the initial high transmittance value after 4000 cycles from the high transmittance state to the low transmittance state. As used herein, an initial high transmittance value is the state of the device prior to application of an electrical potential after manufacture of the device. In some embodiments, the low transmittance value does not change by more than 5% from the initial low transmittance value after 4000 cycles from high transmittance to low transmittance. As used herein, an initial low transmission value is a low transmission value that is reached after a first charge of the device is applied at full voltage. As used herein, transmittance refers to transmittance of the complete visible spectrum and is not limited to a single wavelength.

As for the substrate and the conductive coating on the substrate, those commonly used in solution-based electrochromic devices may be used. For example, the one or both substrates may be glass, metal, plastic, or ceramic. The conductive coating on the one or more substrates may be transparent or opaque depending on the intended use of the device. For example, where the device is a window, both coatings should be substantially transparent, and where the device is a mirror, at least one coating is transparent. Illustrative transparent conductive materials include, but are not limited to, fluorine doped tin oxide (FTO), indium/tin oxide (ITO), doped zinc oxide, indium zinc oxide, metal oxide/Ag/metal oxide, silver nanowire coatings, carbon nanotubes, graphene coatings, wire grids, conductive polymers such as, but not limited to, poly (3, 4-ethylenedioxythiophene) (PEDOT). The opaque conductive coating comprises a metal coating such as rhodium, chromium, nickel, silver, gold, and other metals, or mixtures of any two or more thereof.

In another aspect, provided herein are cationic polymers. The cationic polymer can be transparent and can be formed into a film as described herein. The cationic polymer may have ammonium, pyridinium, imidazolium, or phosphonium functionality; and an oxygen containing backbone. The polymers may also be crosslinked using a crosslinking agent. Illustrative cationic polymers include, but are not limited to, those represented by formula I, formula II, or formula III:

in the above formula, each R¹Independently alkylene, cycloalkylene, or heterocycloalkylene; each R²Is H; each R³Independently absent, -O-or-alkyl-; each R^3aIndependently-alkyl-; each R⁴Independently alkylene, cycloalkylene, or heterocycloalkylene; each R⁵Independently absent, alkylene, cycloalkylene, or heterocycloalkylene; each R⁶Individually absent or alkylene; each R⁷Independently of formula

-[P(R¹³)₃]⁺Or- [ N (R)¹¹)₃]⁺A group of (a); each Cat is a cationic group; each X^-Individually, anionic; each of n, p and r^{1 -5}A repeat unit of an indicator polymer; each q is independently 1, 2 or 3; independently, T is independently absent, is C (O) or is CH₂；R⁸Is alkyl, cycloalkyl or heterocycloalkyl; each R⁹Independently H, F, Br, Cl, NO₂Alkyl, cycloalkyl, alkoxy, aryl or heteroaryl, or any two of R alone⁹The groups may be joined together to form a saturated or unsaturated ring, including with the attachment of R⁹A pyridine ring fused non-aryl or aryl ring of the group; each R¹⁰Independently H, F, Br, Cl, NO₂Alkyl, cycloalkyl, alkoxy, aryl or heteroaryl, or any two of R alone¹⁰The groups may be joined together to form a saturated or unsaturated ring, including with the attachment of R¹⁰A pyridine ring fused non-aryl or aryl ring of the group; each R¹¹Independently an alkyl, cycloalkyl, aryl or heteroaryl group, or any two independent R¹¹The groups may be joined together to form a ring which may be saturated or unsaturated; each R¹²Independently H or alkyl; each R¹³Is alkyl or aryl and each T' is independently absent or is C (O). It is understood that the repeating units identified by brackets are merely a closed representation of an indefinite number of repeating units spaced throughout the polymer. In the case where n, p and r must be oriented only for the sake of clarity^1-5Can be 10 to 100 for n, 2 to 50 for p, and r^1-5Each of which is 25 to 5,000. In some embodiments, this includes 10 to 60 for n, 4 to 20 for p, and r^1-5Each of which is 100 to 3,200. In some embodiments, each R is¹³Is phenyl.

As will be noted, R is in addition to other potential substituents on the polymer⁷The group also provides at least one site for introducing a cationic residue in the polymer. The cationic residue can be from about 10 mole% to about 50 mole%. This may include about 10 mole% to about 40 mole%; about 10 molar% to about 35 molar%; about 10 molar% to about 30 molar%; about 15 molar% to about 50 molar%; about 15 molar% to about 40 molar%; about 15 molar% to about 35 molar%; or from about 15 mol% to about 35 mol%. In some embodiments, the cationic residue can be from about 15 mole% to about 35 mole% of the polymer. In any of the above embodiments, each R is⁷Can be

Alternatively, in any of the above embodiments, each R is⁷Can be

Alternatively, in any of the above embodiments, each R is⁷Can be- [ N (R)¹¹)₃]⁺. Alternatively, in any of the above embodiments, each R is⁷Can be- [ P (R)¹³)₃]⁺。

In any of the above embodiments, each R is¹May be independently C₁-C₆Alkylene radical, C₃-C₁₆Cycloalkylene or C₃-C₁₆Heterocycloalkylene; each R³May be independently C₁-C₆Alkyl radical, C₃-C₁₆Cycloalkyl or C₃-C₁₆A heterocycloalkyl group; each R⁴May be independently C₁-C₆Alkylene radical, C₃-C₁₆Cycloalkylene or C₃-C₁₆Heterocycloalkylene; each R⁵May be absent or C alone₁-C₆Alkylene radical, C₃-C₁₆Cycloalkylene or C₃-C₁₆Heterocycloalkylene; each X^-May be solely anionic. Illustrative examples of anions include, but are not limited to, F^-、Cl^-、Br^-、I^-、BF₄ ^-、PF₆ ^-、SbF₆ ^-、AsF₆ ^-、ClO₄ ^-、N(CF₃SO₂)₂ ^-、C(CF₃SO₂)₃ ^-Triflate (SO)₃CF₃(ii) a Trifluoromethanesulfonate), N (SO)₂C₂F₅)^-、BAr₄ ^-And mixtures of any two or more such anions, wherein Ar is an aryl or fluorinated aryl or a bis (trifluoromethyl) aryl group.

In some embodiments of the above formula, each Cat can be a cationic cyclic group, a cationic heterocyclyl group, a cationic aryl group, or a cationic heteroaryl group. Exemplary Cat groups include a linkage to R at the 1 (i.e., nitrogen position), 2,3, 4, 5, or 6 position of the pyridinium ring³(or attached to an acetal group if R³Absent) pyridinium groupA group attached to R at the 1, 2,3, 4 or 5 position of the imidazolium ring³(or attached to an acetal group if R³Absent) imidazolium groups, or a benzene ring with a phosphonium or ammonium substituent. In some embodiments, the Cat group is a group that is one of:

wherein R is²⁰Is H, alkyl, cycloalkyl or heterocyclyl. In some embodiments, the Cat group is:

wherein R is²⁰Is H, alkyl, cycloalkyl or heterocyclyl. In some embodiments, R³Absent and the Cat group is a group that is one of:

wherein R is²⁰Is H, alkyl, cycloalkyl or heterocyclyl. In some embodiments, R³Absent and Cat groups are:

wherein R is²⁰Is H, alkyl, cycloalkyl or heterocyclyl.

In any embodiment of the above formula, R⁶Can be-CH₂-. In any embodiment of the above formula, R^3aCan be-CH₂-、–CH₂CH₂-、–CH₂CH₂CH₂-、–CH₂CH₂CH₂CH₂-、–CH₂CH₂CH₂CH₂CH₂-or-CH₂CH₂CH₂CH₂CH₂CH₂-。

Illustrative cationic polymers according to formulas I, II and III include, but are not limited to, those of formulas IA-D, IIA-D and IIIA:

in formulas IA-D, IIA-D and IIIA, and as described above, the brackets indicate the repeating units of the polymer. Where specific values are required, they have been stated above.

As noted above, the cationic polymers described herein can be further crosslinked with a crosslinking agent. Illustrative crosslinking agents can include, but are not limited to, di-or tri-isocyanates.

The cationic polymers described herein have a molecular weight of from about 1,000 to about 10,000 daltons. This includes, but is not limited to, an illustrative range such as about 1,000 to about 8,000 daltons; about 1,000 to about 7,000 daltons; about 1,000 to about 6,000 daltons; about 1,500 to about 8,000 daltons; about 1,500 to about 6,000 daltons; about 1,500 to about 5,500 daltons; about 2,000 to about 10,000 daltons; about 2,000 to about 6,000 daltons; about 2,000 to about 5,000 daltons; and about 3,000 to about 6,000 daltons.

In another aspect, a method of making a transparent ion-selective polymeric membrane is provided. The process involves reacting the monomer constituents of the polymer either neat or in a solvent such as propylene carbonate. In the case of polyisocyanates used with diols or triols, as for the preparation of some polymers described by formula I or II, the isocyanate to hydroxyl ratio can be from about 1.00 to about 1.10. A catalyst may be used in the reaction. For example, in some embodiments, an organotin catalyst may be used to effect the isocyanate/alcohol reaction. Once the polymers have been formed, they can be cast or drawn on a release liner (i.e., polyethylene terephthalate or polytetrafluoroethylene) and the solvent removed, or the polymers allowed to cure at room or elevated temperatures. A second release liner can be used over the polymer in an interlayer fashion, if desired.

The invention thus generally described will be more readily understood by reference to the following embodiments, which are provided by way of illustration and are not intended to be limiting of the invention.