Membrane for reference electrode

Abstract

Described is a reference electrode membrane having one or more conductive salts and one or more polyurethanes, polypropylenes or cellulose materials. Also described is a reference electrode having a contact electrode having the reference electrode membrane as described herein on a surface thereof, and a method of making a reference electrode including providing a solution having one or more conductive salts, one or more polyurethanes, polypropylenes or cellulose materials, and one or more solvents, providing the solution on a surface of a contact electrode, and drying the solution to provide a reference electrode membrane on the contact electrode.

Description

MEMBRANE FOR REFERENCE ELECTRODETECHNICAL FIELD

[0001] This disclosure relates generally to the field of reference electrode membranes, reference electrodes incorporating the same, and methods of making the same.BACKGROUND

[0002] In electrochemical devices having reference electrodes, it is critical that the reference electrodes provide stable potential and / or voltage for optimum performance (e.g., for improved measurement accuracy and / or precision, for more controlled bias voltage applications on the sensing electrode, etc.). However, current reference electrodes often lack stability in the presence of certain interferent substances (i.e., components in a sample that may provide a positive or negative bias for the ion of interest). Common interferent substances include bromide, iodide, and chloride ions. In addition, while some reference electrodes show stability in the presence of certain interferent substances, they often show unacceptable responses to other interferent substances. There is thus a need in the art for reference electrodes that can withstand a variety of common interfering ions.SUMMARY

[0003] Disclosed herein is a reference electrode membrane having at least one conductive salt and at least one polyurethane, polypropylene, cellulose material, conductive material, or a combination thereof. The disclosure is also directed to a reference electrode having a reference electrode membrane as described herein. Further disclosed are methods of making the reference electrode membranes and reference electrodes as described herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0004] FIG. 1 A shows a cross-section view of a first example reference electrode according to aspects of the present disclosure.

[0005] FIG. IB shows a cross-section view of a second example reference electrode according to aspects of the present disclosure.

[0006] FIG. 1C shows a cross-section view of a third example reference electrode according to aspects of the present disclosure.

[0007] FIG. 2A shows a cross-section view of an example potentiometric cell assembly according to aspects of the present disclosure.

[0008] FIG. 2B shows a top view of potentiometric cell assembly as described in relation to FIG. 2A.

[0009] FIG. 3 shows a schematic of transducer chip having reference electrodes according to aspects of the present disclosure.

[0010] FIG. 4 shows a schematic of transducer chip having a cove Ag / AgCl electrode as described in relation to Example II.

[0011] FIG. 5 A shows a linear sensitivity plot corresponding with Table 2 of Example II.

[0012] FIG. 5B shows a linear sensitivity plot corresponding with Table 2 of Example II.

[0013] FIG. 5C shows a linear sensitivity plot corresponding with Table 2 of Example II.

[0014] FIG. 5D shows a linear sensitivity plot corresponding with Table 2 of Example II.

[0015] FIG. 5E shows a linear sensitivity plot corresponding with Table 2 of Example II.

[0016] FIG. 5F shows a linear sensitivity plot corresponding with Table 2 of Example II.

[0017] FIG. 6 A shows the interference effect of bromide and iodide ions on reference electrodes as described in Example III.

[0018] FIG. 6B shows the interference effect of bromide and iodide ions on reference electrodes as described in Example III.

[0019] FIG. 6C shows the interference effect of bromide and iodide ions on reference electrodes as described in Example III.

[0020] FIG. 7 A shows a linear sensitivity plot corresponding with Table 4 of Example IV.

[0021] FIG. 7B shows a linear sensitivity plot corresponding with Table 4 of Example IV.

[0022] FIG. 7C shows a linear sensitivity plot corresponding with Table 4 of Example IV.

[0023] FIG. 7D shows a linear sensitivity plot corresponding with Table 4 of Example IV.

[0024] FIG. 8 A shows a sensitivity plot corresponding with Table 5 of Example V.

[0025] FIG. 8B shows a sensitivity plot corresponding with Table 5 of Example V.DETAILED DESCRIPTION

[0026] Disclosed herein is a reference electrode membrane having at least one conductive salt and at least one polyurethane, polypropylene, cellulose material, conductive material or a combination thereof. The disclosure is also directed to a reference electrode having a reference electrode membrane as described herein. Further disclosed are methods of making the reference electrode membranes and reference electrodes as described herein.

[0027] As used herein, a “reference electrode” refers to an electrode having a known potential against which the potential of another electrode can be measured. According to some aspects, a reference electrode may include a reference electrode membrane that is impermeable to one or more interferent substances that can affect the known potential of the reference electrode.

[0028] The reference electrode membrane of the present disclosure may include one or more polyurethanes. In some non-limiting examples, the one or more polyurethanes may each independently have one or more hydrophilic functional groups, one or more hydrophobic functional groups, or a combination thereof. Example hydrophobic functional groups include, but are not limited to, hydrophobic diols, polyester hydrophobic polyols, and combinations thereof. Non-limiting examples of polyurethanes useful according to the present disclosure include those described in U.S. Patent Publication No. 2015 / 368392 and U.S. Patent No. 8,802,770, the contents of which are expressly incorporated by reference herein. In some non-limiting examples, the one or more polyurethanes may absorb a certain equilibrium water content, such as no more than about 60% by weight of the dry resin, optionally no more than about 35% by weight of the dry resin, optionally no more than about 20% by weight of the dry resin, and optionally no more than about 10% by weight of the dry resin. In one non-limiting example, the one or more polyurethanes may include a Tecophilic™ thermoplastic polyurethane (TPU) grade HP-60D-20, HP-60D-35 and / or grade HP60D-10 distributed by Lubrizol.

[0029] According to some aspects, the reference electrode membrane of the present disclosure may include the one or more polyurethanes at a concentration of between about 1 and 45% w / w, optionally between about 1 and 15% w / w, optionally between about 5 and 10% w / w, optionally between about 20 and 45% w / w, optionally between about 25 and 40% w / w, optionally between about 25 and 30% w / w, optionally between about 31 and 35% w / w, and optionally between about 36 and 40% w / w.

[0030] Additionally or alternatively, the reference electrode membrane of the present disclosure may include one or more polypropylenes.

[0031] According to some aspects, the reference electrode membrane of the present disclosure may include the one or more polypropylenes at a concentration of between about 20 and 45% w / w, optionally between about 25 and 40% w / w, optionally between about 25 and 30% w / w, optionally between about 31 and 35% w / w, and optionally between about 36 and 40% w / w.

[0032] Additionally or alternatively, the reference electrode membrane of the present disclosure may include one or more cellulose materials, including, but not limited to, cellulose acetate. According to some aspects, the reference electrode membrane of the present disclosure may include the one or more cellulose materials at a concentration of between about 20 and 45% w / w, optionally between about 25 and 40% w / w, optionally between about 25 and 30% w / w, optionally between about 31 and 35% w / w, and optionally between about 36 and 40% w / w.

[0033] According to some aspects, the reference electrode membrane of the present disclosure may include one or more conductive salts. According to some aspects, the one or more conductive salts may include one or more inorganic salts, one or more organic salts, or a combination thereof.

[0034] Non-limiting examples of organic salts according to the present disclosure include formates, acetamides, acetates, butyrates, benzoates, carboxylates, alkoxides, phenolates, oxalates, malonates, tartrates, malates, citrates, gluconates, maleates, sorbates, stearates, lactates, glycerates, urates, diazonium salts, iminium salts, phosphinates, organophosphates, mesylates, bechgaard salts, picolinates, salts of cocaine, salts of morphine, monosodium glutamate, trolamine salicylate, triphenylmethyl hexafluorophosphate, choline chloride, copper ibuprofenate, homatropine methylbromide, mellite, tetrapropylammonium perruthenate, collidinium p-toluenesulfonate, pyridinium chloride, tetrasodium edta, lithium diisopropylamide, lithium bis(trimethylsilyl)amide, potassium trispyrazolylborate, room temperature ionic liquids (RTILs), and combinations thereof.

[0035] Non-limiting examples of inorganic salts according to the present disclosure include phosphates, sulphates, sulphites, bromides, carbonates, chlorides, chlorates, fluorides, iodates, iodides, nitrates, molybdates, selenites, oxides, silicates, and combinations thereof.

[0036] In some non-limiting examples, the one or more conductive salts may include sodium salts, potassium salts, lithium salts, or a combination thereof. According to some aspects, the one or more conductive salts may include sodium chloride, potassium chloride, lithium chloride, sodium iodide, potassium iodide, lithium iodide, or a combination thereof

[0037] According to some aspects, the reference electrode membrane of the present disclosure may include the one or more conductive salts at a concentration of between about 0.01 and 10% w / w, optionally between about 1 and 10% w / w, optionally between about 0.01 and 3% w / w, and optionally between about 3 and 8% w / w.

[0038] According to some aspects, the reference electrode membrane of the present disclosure may further include one or more polymeric resin components. In some non-limiting examples, the one or more polymeric resin components may include one or more polyvinyl-based materials. Non-limiting examples of polyvinyl-based materials according to the present disclosure include PVA (polyvinyl-alcohol), PVP (polyvinyl-pyrrolidone), PVB (polyvinyl -butyral), PVC (polyvinyl-chloride), methacrylates (HEMA), and combinations thereof.

[0039] According to some aspects, the reference electrode membrane of the present disclosure may include the one or more polymeric resin components at a concentration of between about 10 and 30% w / w, optionally between about 15 and 25% w / w, optionally between about 20 and 25% w / w, optionally between about 45 and 75% w / w, optionally between about 50 and 70% w / w, optionally between about 55 and 68% w / w, optionally between about 55 and 60% w / w, and optionally between about 61 and 68% w / w.

[0040] The reference electrode membrane of the present disclosure may include one or more conductive materials. In some examples, the one or more conductive materials may be sufficient to reduce or eliminate membrane impedance of the reference electrode membrane. In some non-limiting examples, the conductive material may include one or more metals, one or more conductive carbon-containing materials, one or more conductive polymers, or a combination thereof.

[0041] Example metals according to the present disclosure include, but are not limited to, silver, platinum, gold, iridium, palladium, copper, aluminum, nickel, zinc, iron, and alloys and combinations thereof.

[0042] Example conductive carbon-containing materials according to the present disclosure include, but are not limited to, graphene, graphite, carbon nanotubes, carbon black, activated carbon, and combinations thereof.

[0043] Example conductive polymers according to the present disclosure include, but are not limited to, polyaniline (PANI), polypyrrole (PPy), poly(3,4-ethylenedioxythiophene) (PEDOT), polyacetylene, polythiophene, polyphenylene vinylene (PPV), and combinations thereof.

[0044] According to some aspects, at least one of the one or more conductive materials may be provided in the form of particles. Additionally or alternatively, at least one of the one or more conductive materials may be provided in the form of a paste. In one non-limiting example, the conductive material may include DM-SIP-3060S, DM-SIP-3071S, DM-SIP- 14031S, DM-SIP-3101S, and / or DM-SIP-3063S, manufactured by Dycotec Materials, and / or JS-A102A, manufactured by NovaCentrix.

[0045] According to some aspects, the reference electrode membrane of the present disclosure may include the one or more conductive materials at a concentration between about 40 and 90% w / w, optionally between about 50 and 80% w / w, and optionally between about 60 and 70 % w / w. According to some aspects, the reference electrode membrane of the present disclosure may include the one or more conductive materials at a concentration of at least about 40% w / w, optionally at least about 45% w / w, optionally at least about 50% w / w, optionally at least about 55% w / w, and optionally at least about 69% w / w.

[0046] According to some aspects, the reference electrode membrane of the present disclosure may include the one or more polyurethanes and the one or more conducive salts at a weight ratio between about 50: 1 to 1 :50, optionally between about 20: 1 and 1 :20, optionally between about 1 : 10 and 10: 1, optionally between about 1 :5 and 5: 1, optionally between about 1 :1 and 1 :50, optionally between about 1 : 1 and 1 :20, optionally between about 1 : 1 and 1 :10, optionally between about 1 : 1 and 1 :5, optionally between 50: 1 and 1 : 1, optionally between about 20: 1 and 1 : 1, optionally between about 10: 1 and 1 : 1, and optionally between about 5: 1 and 1 :1.

[0047] According to some aspects, the reference electrode membrane of the present disclosure may include the one or more polyurethanes and the one or more polymeric resin components at a weight ratio of between about 1 :50 and 20: 1, optionally between about 1 :50 and 10: 1, optionally between about 1 :20 and 10: 1, optionally between about 1 :5 and 1 : 1, optionally between about 1 :50 and 1 : 1, optionally between about 1 :30 and 1 : 1, optionally between about 1 :20 and 1 : 1, optionally between about 1 : 1 and 20: 1, and optionally between about 1 : 1 and 10: 1.

[0048] According to some aspects, the reference electrode membrane of the present disclosure may include the one or more conducive salts and the one or more polymeric resin components at a weight ratio of between about 5: 1 and 1 :50, and optionally between about 1 : 1 and 1 :50.

[0049] According to some aspects, the reference electrode membrane of the present disclosure may include the one or more conductive materials and the one or more conducive salts at a weight ratio of between about 1 : 1 and 100: 1, and optionally between about 25:1 and 75:l.

[0050] According to some aspects, the reference electrode membrane of the present disclosure may include the one or more conductive materials and the one or more polymeric resin components at a weight ratio of between about 1 : 1 and 10: 1, and optionally between about 1 : 1 and 5: 1.

[0051] According to some aspects, the reference electrode membrane of the present disclosure may include the one or more conductive materials and the one or more polyurethanes at a weight ratio of between about 1 : 1 and 20: 1, and optionally between about 1 : 1 and 10: 1.

[0052] The present disclosure is also directed to a reference electrode having a reference electrode membrane as described herein. According to some aspects, the reference electrode may include a contact electrode with a reference electrode membrane on a surface thereof. According to some aspects, the contact electrode may include an electrical conductor as known in the art. Non-limiting examples of electrical conductors include metallic-based conductors (e.g., silver, silver chloride, silver bromide, silver iodide, gold, platinum, copper, aluminum, and combinations thereof), a conductive polymer, graphite, and combinations thereof.

[0053] FIG. 1 A shows a cross-section view of an example reference electrode according to aspects of the present disclosure. As shown in FIG. 1 A, the reference electrode 100 may include areference electrode membrane 101 as described herein provided on a surface of a contact electrode 102. According to some aspects, contact electrode 102 may include an electrical conductor. As shown in FIG. 1A, reference electrode 100 may further include an electrically insulated substrate 103 at least partially surrounding reference electrode membrane 101. Insulated substrate 103 may include one or more insulating materials. As shown, insulating substrate 103 may define a well for reference electrode membrane 101. In some non-limiting examples, the insulating material may include a polymer (e.g., a polyimide, a liquid crystal polymer, polyvinyl chloride (PVC), a polycarbonate (PC), a polyester), silicon, silicon nitride, an epoxy, glass, ceramic, plastic, or a combination thereof.

[0054] As shown in FIG. 1A, insulated substrate 103 may form one or more walls of a cavity in which contact electrode 102 (having reference electrode membrane 101 on a surface thereof) is provided. However, it should be understood that the present disclosure is not necessarily limited to this example. It should also be understood that while FIG. 1 A shows insulated substrate 103 forming a single cavity containing reference electrode membrane 101, the disclosure is not limited in this way. For example, substrate 103 may include two, three, four, five, or more cavities, each independently including an electrode that is the same as or different from the electrode of another cavity. For example, each cavity may independently contain a reference electrode that is the same as or different from a reference electrode contained in another cavity. Additionally or alternatively, each cavity may independently contain an ion selective electrode having an ion selective membrane that is the same as or different from the ion selective electrode membrane contained in another cavity.

[0055] FIG. IB shows another example of a reference electrode 100 according to aspects of the present disclosure. Like FIG. 1A, FIG. IB shows a contact electrode 102 and an insulated substrate 103. In this example, contact electrode 102 and insulated substrate 103 form a substantially flat surface on which reference electrode membrane 101 may be provided.

[0056] FIG. 1C shows another example of a reference electrode 100 according to aspects of the present disclosure. In this example, contact electrode 102 may protrude relative to an insulated substrate 103 as shown. Contact electrode 102 may include any shape suitablefor a reference electrode, such as a plate or a wire. In this example, reference electrode membrane 101 may be provided so as to at least partially cover contact electrode 102.

[0057] According to some aspects, the reference electrode of the present disclosure may further include one or more additional layers, such as a “capping layer” configured to reduce and / or eliminate potential diffusion of interferent substances as disclosed herein. In some non-limiting examples, the capping layer may include one or more capping agents, including one or more cellulose materials such as cellulose acetate and / or one or more polyurethanes having one or more hydrophobic functional groups as described herein. The capping layer may be provided on a first surface of the electrode reference membrane as described herein, the first surface being opposite the contact electrode.

[0058] Further disclosed are methods of making the reference electrode membranes and reference electrodes as described herein. According to some aspects, the method may include providing a solution containing one or more components of the reference electrode membrane as described herein, providing the solution on a surface, and drying the solution to provide a reference electrode membrane as described herein.

[0059] According to some aspects, the solution may contain at least one conductive salt, at least one polyurethane, at least one polymeric resin component, at least one conductive material, or a combination thereof. The solution may further contain at least one solvent sufficient to solubilize the one or more components of the reference electrode membrane as described herein. In some non-limiting examples, the at least one solvent may include an organic solvent. Non-liming examples of organic solvents useful according to the present disclosure may include tetrahydrofuran (THF), dimethyl sulfate (DMS), methanol (MeOH), ethanol (EtOH), cyclohexanone, dimethylacetamide, or a combination thereof. According to some aspects, the solvent may include at least two components, such as at least two organic solvents as described herein,

[0060] According to some aspects, the solution may have a concentration of the one or more components of the reference electrode membrane sufficient to provide a reference electrode membrane as described herein.

[0061] In some non-limiting examples, the solution may have at least one conductive salt, wherein a total amount of conductive salts provided in the solution is between about 0.1 and 1.5%w / w, optionally between about 0.1 and 1.25% w / w, optionally between about 0.1 and 1% w / w, optionally between about 0.2 and 1% w / w.

[0062] According to some aspects, each of the at least one conductive salts may be provided in the solution at a concentration of between about 0.1 and 5% w / w, optionally between about 0.1 and 2.5% w / w, optionally between about 0.1 and 1.5% w / w, optionally between about 0.1 and 1.25% w / w, optionally between about 0.1 and 1% w / w, and optionally between about 0.2 and 1% w / w.

[0063] According to some aspects, each of the at least one conductive salts may be provided in the solution at a concentration of about 0.1% w / w, optionally about 0.2% w / w, optionally about 0.3% w / w, optionally about 0.4% w / w, optionally about 0.5% w / w, optionally about 0.6% w / w, optionally about 0.6% w / w, optionally about 0.8% w / w, optionally about 0.9% w / w, optionally about 1% w / w, and optionally about 1.1% w / w.

[0064] In some non-limiting examples, the solution may have at least one polyurethane, wherein a total amount of polyurethanes provided in the solution is between about 0.1 and 10% w / w, optionally between about 1 and 6% w / w, optionally between about 1 and 5.5% w / w, optionally between about 1.1 and 5.3% w / w.

[0065] According to some aspects, each of the at least one polyurethanes may be provided in the solution at a concentration of between about 1 and 6% w / w, optionally between about 1 and 5.5% w / w, optionally between about 1.1 and 5.3% w / w.

[0066] According to some aspects, each of the at least polyurethanes may be provided in the solution at a concentration of about 1% w / w, optionally about 1.1% w / w, optionally about1.2% w / w, optionally about 1.3% w / w, optionally about 1.4% w / w, optionally about 1.5% w / w, optionally about 1.6% w / w, optionally about 1.7% w / w, optionally about 1.8% w / w, optionally about 1.9% w / w, optionally about 2% w / w, optionally about 2.1% w / w, optionally about 2.2% w / w, optionally about 2.3% w / w, optionally about 2.4% w / w, optionally about 2.5% w / w, optionally about 2.6% w / w, optionally about 2.7% w / w, optionally about 2.8% w / w, optionally about 2.9% w / w, optionally about 3% w / w, optionally about 3.1% w / w, optionally about 3.2% w / w, optionally about 3.3% w / w, optionally about 3.4% w / w, optionally about 3.5% w / w, optionally about 3.6% w / w, optionally about 3.7% w / w, optionally about 3.8% w / w, optionally about 3.9% w / w, optionally about 4% w / w, optionally about 4.1% w / w, optionally about 4.2% w / w,optionally about 4.3% w / w, optionally about 4.4% w / w, optionally about 4.5% w / w, optionally about 4.6% w / w, optionally about 4.7% w / w, optionally about 4.8% w / w, optionally about 4.9% w / w, optionally about 5% w / w, optionally about 5.1% w / w, optionally about 5.2% w / w, optionally about 5.3% w / w, optionally about 5.4% w / w, optionally about 5.5% w / w, optionally about 5.6% w / w, optionally about 5.7% w / w, optionally about 5.8% w / w, optionally about 5.9% w / w, and optionally about 6% w / w.

[0067] In some non-limiting examples, the solution may have at least one polymeric resin components, wherein a total amount of polymeric resin components provided in the solution is between about 1 and 15% w / w, optionally between about 2 and 14% w / w, optionally between about 2 and 13% w / w.

[0068] According to some aspects, each of the at least one polymeric resin components may be provided in the solution at a concentration of between about 1 and 6% w / w, optionally between about 1 and 15% w / w, optionally between about 2 and 14% w / w, optionally between about 2 and 13% w / w.

[0069] According to some aspects, each of the at least one polymeric resin components may be provided in the solution at a concentration of about 1% w / w, optionally about 1.1% w / w, optionally about 1.2% w / w, optionally about 1.3% w / w, optionally about 1.4% w / w, optionally about 1.5% w / w, optionally about 1.6% w / w, optionally about 1.7% w / w, optionally about 1.8% w / w, optionally about 1.9% w / w, optionally about 2% w / w, optionally about 2.1% w / w, optionally about 2.2% w / w, optionally about 2.3% w / w, optionally about 2.4% w / w, optionally about 2.5% w / w, optionally about 2.6% w / w, optionally about 2.7% w / w, optionally about 2.8% w / w, optionally about 2.9% w / w, optionally about 3% w / w, optionally about 3.1% w / w, optionally about 3.2% w / w, optionally about 3.3% w / w, optionally about 3.4% w / w, optionally about 3.5% w / w, optionally about 3.6% w / w, optionally about 3.7% w / w, optionally about 3.8% w / w, optionally about 3.9% w / w, optionally about 4% w / w, optionally about 4.1% w / w, optionally about 4.2% w / w, optionally about 4.3% w / w, optionally about 4.4% w / w, optionally about 4.5% w / w, optionally about 4.6% w / w, optionally about 4.7% w / w, optionally about 4.8% w / w, optionally about 4.9% w / w, optionally about 5% w / w, optionally about 5.1% w / w, optionally about 5.2% w / w, optionally about 5.3% w / w, optionally about 5.4% w / w, optionally about 5.5% w / w, optionally about 5.6% w / w,optionally about 5.7% w / w, optionally about 5.8% w / w, optionally about 5.9% w / w, optionally about 6% w / w, optionally about 6% w / w, optionally about 6.1% w / w, optionally about 6.2% w / w, optionally about 6.3% w / w, optionally about 6.4% w / w, optionally about 6.5% w / w, optionally about 6.6% w / w, optionally about 6.7% w / w, optionally about 6.8% w / w, optionally about 6.9% w / w, optionally about 7% w / w, optionally about 7.1% w / w, optionally about 7.2% w / w, optionally about 7.3% w / w, optionally about 7.4% w / w, optionally about 7.5% w / w, optionally about 7.6% w / w, optionally about 7.7% w / w, optionally about 7.8% w / w, optionally about 7.9% w / w, optionally about 8% w / w, optionally about 8.1% w / w, optionally about 8.2% w / w, optionally about 8.3% w / w, optionally about 8.4% w / w, optionally about 8.5% w / w, optionally about 8.6% w / w, optionally about 8.7% w / w, optionally about 8.8% w / w, optionally about 8.9% w / w, optionally about 9% w / w, optionally about 9.1% w / w, optionally about 9.2% w / w, optionally about 9.3% w / w, optionally about 9.4% w / w, optionally about 9.5% w / w, optionally about 9.6% w / w, optionally about 9.7% w / w, optionally about 9.8% w / w, optionally about 9.9% w / w, optionally about 10% w / w, optionally about 10.1% w / w, optionally about 10.2% w / w, optionally about 10.3% w / w, optionally about 10.4% w / w, optionally about 10.5% w / w, optionally about 10.6% w / w, optionally about 10.7% w / w, optionally about 10.8% w / w, optionally about 10.9% w / w, optionally about 11% w / w, optionally about 11.1% w / w, optionally about 11.2% w / w, optionally about 11.3% w / w, optionally about 11.4% w / w, optionally about 11.5% w / w, optionally about 11.6% w / w, optionally about 11.7% w / w, optionally about 11.8% w / w, optionally about 11.9% w / w, optionally about 12% w / w, optionally about 12.1% w / w, optionally about 12.2% w / w, optionally about 12.3% w / w, optionally about 12.4% w / w, optionally about 12.5% w / w, optionally about 12.6% w / w, optionally about 12.7% w / w, optionally about 12.8% w / w, and optionally about 12.9% w / w.

[0070] In some non-limiting examples, the solution may have at least one conductive material, wherein a total amount of conductive material provided in the solution is between about 1 and 20% w / w, optionally between about 1 and 10% w / w, optionally between about 10 and 20% w / w, and optionally between about 5 and 15% w / w.

[0071] In some non-limiting examples, the solution may have at least one conductive material, wherein a total amount of conductive material provided in the solution is about 7.0% w / w,optionally about 7.1% w / w, optionally about 7.2% w / w, optionally about 7.3% w / w, optionally about 7.4% w / w, optionally about 7.5% w / w, optionally about 7.6% w / w, optionally about 7.7% w / w, optionally about 7.8% w / w, optionally about 7.9% w / w, optionally about 8.0% w / w, optionally about 8.1% w / w, optionally about 8.2% w / w, optionally about 8.3% w / w, optionally about 8.4% w / w, optionally about 8.5% w / w, optionally about 8.6% w / w, optionally about 8.7% w / w, optionally about 8.8% w / w, optionally about 8.9% w / w, optionally about 9.0% w / w, optionally about 9.1% w / w, optionally about 9.2% w / w, optionally about 9.3% w / w, optionally about 9.4% w / w, optionally about 9.5% w / w, optionally about 9.6% w / w, optionally about 9.7% w / w, optionally about 9.8% w / w, optionally about 9.9% w / w, optionally about 10.0% w / w, optionally about 10.1% w / w, optionally about 10.2% w / w, optionally about 10.3% w / w, optionally about 10.4% w / w, optionally about 10.5% w / w, optionally about 10.6% w / w, optionally about 10.7% w / w, optionally about 10.8% w / w, optionally about 10.9% w / w, optionally about 11.0% w / w, optionally about 11.1% w / w, optionally about 11.2% w / w, optionally about 11.3% w / w, optionally about 11.4% w / w, optionally about 11.5% w / w, optionally about 11.6% w / w, optionally about 11.7% w / w, optionally about 11.8% w / w, and optionally about 11.9% w / w.

[0072] According to some aspects, the solution may have at least one solvent, wherein a total amount of solvent in the solution is between about 70 and 99.9% w / w, optionally between about 80 and 99% w / w, optionally between about 80 and 98% w / w, and optionally between about 80 and 97% w / w.

[0073] According to some aspects, each of the at least one solvents may be provided in the solution at a concentration of between about 20% and 99.9% w / w, optionally between about 30 and 99.9% w / w, optionally between about 21 and 29% w / w, optionally between about 30 and 40% w / w, optionally between about 41 and 50% w / w, optionally between about 51 and 60% w / w, optionally between about 61 and 70% w / w, optionally between about 71 and 80% w / w, optionally between about 81 and 90% w / w, and optionally between about 91 and 99.9% w / w.

[0074] According to some aspects, the solution may include the one or more polyurethanes and the one or more conducive salts at a weight ratio of between about 50: 1 to 1 :50, optionally between about 20: 1 and 1 :20, optionally between about 1 : 10 and 10: 1, optionally betweenabout 1:5 and 5:1, optionally between about 1:1 and 1:50, optionally between about 1:1 and 1:20, optionally between about 1:1 and 1:10, optionally between about 1:1 and 1:5, optionally between 50:1 and 1:1, optionally between about 20:1 and 1:1, optionally between about 10:1 and 1:1, and optionally between about 5:1 and 1:1.

[0075] According to some aspects, the solution may include the one or more polyurethanes and the one or more polymeric resin components at a weight ratio of between about 1:50 and 20:1, optionally between about 1:50 and 10:1, optionally between about 1:20 and 10:1, optionally between about 1:5 and 1:1, optionally between about 1:50 and 1:1, optionally between about 1 :20 and 1:1, optionally between about 1 : 1 and 20: 1, and optionally between about 1:1 and 10:1.

[0076] According to some aspects, the solution may include the one or more conducive salts and the one or more polymeric resin components at a weight ratio of between about 5:1 and 1:50, and optionally between about 1:1 and 1:50.

[0077] According to some aspects, the solution may include the one or more conductive materials and the one or more conducive salts at a weight ratio of between about 1 : 1 and 100: 1, and optionally between about 25 : 1 and 75 : 1.

[0078] According to some aspects, the solution may include the one or more conductive materials and the one or more polymeric resin components at a weight ratio of between about 1:1 and 10:1, and optionally between about 1:1 and 5:1.

[0079] According to some aspects, the solution may include the one or more conductive materials and the one or more polyurethanes at a weight ratio of between about 1:1 and 20:1, and optionally between about 1:1 and 10:1.

[0080] According to some aspects, the method may further include providing the solution on a surface. In some non-limiting examples, the surface may include an inert surface. Additionally or alternatively, the surface may include components of a reference electrode as described herein. For example, the solution may be provided on a surface of a contact electrode as described herein. In some non-limiting examples, the contact electrode may be provided within a cavity formed in an insulated substrate as described herein. According to some aspects, the solution may be provided on the surface in a reduced moisture environment. As used herein, the term “reduced moisture environment” may refer to an environment having 30% RH or less.

[0081] According to some aspects, the method may further include drying the solution to provide a reference electrode membrane as described herein. The solution may be dried at a drying temperature for a drying time sufficient for all or a portion of the solvent to evaporate. It should be understood that drying temperatures and drying times may depend on the concentration of solvent in the solution and / or the amount of solution to be dried.

[0082] In some non-limiting examples, the drying temperature may be room temperature (i.e., about 20 to 22 °C). In some non-limiting examples, the drying temperature may be performed at an elevated temperature, such as between about 40 and 120 °C, optionally between about 40 and 90 °C, optionally between about 40 and 80 °C, optionally between about 50 and 70 °C, optionally about 54.4 °C, optionally about 65.5 °C, and optionally about 60 °C. In some non-limiting examples, the drying time may be between about 10 minutes and 24 hours, optionally between about 10 minutes and 12 hours, optionally between about 1 hour and 10 hours, optionally at least about 2 hours, optionally at least about 8 hours, and optionally at least about 12 hours. According to some aspects, the solution may be dried in a reduced moisture environment, such as in an oven, a machine mounted dehumidifying dryer, a dehumidifying dryer hopper, and / or a one shot loader. As used here, in the term “reduced moisture environment” refers to an environment having a maximum moisture level of about 0.05%. In one non-limiting example, the solution may be dried in a machine mounted dehumidifying dryer (a desiccant dryer delivering air at 1 liter / sec / kg at -40°C dew point (1 cfm / lb at -40°F dew point)).

[0083] It should be understood that the present disclosure is also directed to methods of making the reference electrodes as described herein. According to some aspects, the method may include providing a solution containing one or more components of the reference electrode membrane as described herein, providing the solution on a surface, and drying the solution to provide a reference electrode as described herein. The method may optionally include providing a capping layer on a first surface of the reference electrode membrane as described herein. For example, the method may further include providing a capping solution containing one or more capping agents in a solvent, providing the capping solution on the first surface of the reference electrode membrane, the first surface being opposite the contact electrode, and drying the solution to provide a capping layer. According to some aspects, the capping solution may include any solvent as disclosed herein. In some non-limiting examples, the capping agent may be provided in the capping solution at a concentration of between about 0.01 and 50% w / w, optionally between about 0.01 and 25% w / w, and optionally between about 0.01 and 25% w / w.

[0084] According to some aspects, the reference electrodes of the present disclosure may, in conjunction with one or more other components, form an assembly for electrochemical measurements, such as a potentiometric assembly, a voltametric assembly, an amperometric assembly, an impedimetric assembly, and / or a coulometric assembly. In one non-limiting example, the reference electrodes of the present disclosure may, in conjunction with one or more ion selective electrodes, form a potentiometric cell assembly.

[0085] FIG. 2A shows a cross-section view of an example potentiometric cell assembly 200 according to aspects of the present disclosure. As shown in FIG. 2A, potentiometric cell assembly 200 may include an insulated substrate 203, similar to insulated substrate 103 as described in relation to FIG. 1 A. Potentiometric cell assembly 200 may further include a reference electrode 202b as described herein. FIG. 2A further shows an ion selective electrode membrane 201 and a reference electrode membrane 206 as described herein.

[0086] It should be understood that potentiometric cell assembly 200 may be provided in contact with a sample 204 in order to determine a concentration of ions 205 contained therein, as known in the art. In particular, the concentration of ions 205 contained in sample 204 may be determined using Nernst Equation (I):Equation (I)

[0087] wherein Eo is the standard potential, R is the universal gas constant, T is the temperature in Kelvin, n is the ion charge, F is the Faraday constant and Ai and A2 are the ion concentrations.

[0088] FIG. 2B shows a top view of potentiometric cell assembly 200 as described in relation to FIG. 2A.

[0089] It should be understood, however, that the assembly shown in FIGs. 2A and 2B is not particularly limiting. For example, the ion selective electrodes may not contain a membrane and may consist of a solid electrode formed from an electrical conductor as disclosed herein. In other examples, the ion selective electrodes may contain a polymer membrane.

[0090] FIG. 3 shows a schematic of transducer chip having a reference electrode as described herein. In particular, FIG. 3 shows a transducer chip 300 having a first reference electrode 301 having a first reference electrode membrane as disclosed herein. Transducer chip 300 may further include a plurality of ion selective electrodes 302, each optionally having an ion selective electrode membrane. While not shown, transducer chip 300 may optionally include an external reference electrode. It should be understood, however, that the reference electrodes as described herein are not limited to the application shown in FIG. 3. For example, the reference electrodes of the present disclosure may be used as a reference electrode in an electrochemical sensor as described in U.S. Patent Publication No. 2023 / 0304958, the contents of which are incorporated herein in their entirety by reference.

[0091] Herein, the recitation of numerical ranges by endpoints (e.g. between about 50: 1 and 1 : 1, between about 100 and 500 °C, between about 1 minute and 60 minutes) include all numbers subsumed within that range, for example, between about 1 minute and 60 minutes includes 21, 22, 23, and 24 minutes as endpoints within the specified range. Thus, for example, ranges 22-36, 25-32, 23-29, etc. are also ranges with endpoints subsumed within the range 1-60 depending on the starting materials used, temperature, specific applications, specific embodiments, or limitations of the claims if needed. The Examples and methods disclosed herein demonstrate the recited ranges subsume every point within the ranges because different synthetic products result from changing one or more reaction parameters. Further, the methods and Examples disclosed herein describe various aspects of the disclosed ranges and the effects if the ranges are changed individually or in combination with other recited ranges.

[0092] Further, the word “example” is used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “example” is not necessarily to be construed as preferred or advantageous over other aspects. Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C,” “at least one of A, B, and C,” and “A, B, C, or any combination thereof’ include any combination of A, B, and / or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C,” “at least one of A, B, and C,” and “A, B, C, or any combination thereof’ may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one ormore member or members of A, B, or C. Nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims.

[0093] As used herein, the term “about” and “approximately” are defined to being close to as understood by one of ordinary skill in the art. In one non-limiting embodiment, the term “about” and “approximately” are defined to be within 5%.

[0094] Thus, based on the foregoing, the present disclosure may be implemented according to any one of the following clauses.

[0095] Clause 1. A reference electrode membrane, comprising:

[0096] one or more conductive salts, and

[0097] one or more polyurethanes.

[0098] Clause 2. The reference electrode membrane according to clause 1, further comprising one or more polymeric resin components.

[0099] Clause 3. The reference electrode membrane according to clause 2, wherein the one or more polymeric resin components comprise one or more polyvinyl-based materials.

[0100] Clause 4. The reference electrode membrane according to clause 1, wherein the one or more conductive salts comprise a chloride salt.

[0101] Clause 5. The reference electrode membrane according to clause 1, wherein the one or more polyurethanes comprise a polyurethane having one or more hydrophobic functional groups.

[0102] Clause 6. The reference electrode membrane according to clause 1, wherein the one or more polyurethanes comprise a polyurethane having one or more hydrophilic functional groups.

[0103] Clause 7. The reference electrode membrane according to clause 1, further comprising one or more conductive materials comprising one or more metals, one or more conductive carbon-containing materials, one or more conductive polymers, or a combination thereof.

[0104] Clause 8 A reference electrode, comprising:

[0105] a contact electrode having the reference electrode membrane according to clause 1 on a surface thereof.

[0106] Clause 9. The reference electrode according to clause 8, wherein the contact electrode comprises an electrical conductor selected from silver, silver chloride, silver bromide, silver iodide, gold, platinum, copper, aluminum, and combinations thereof.

[0107] Clause 10. The reference electrode according to clause 8, further comprising a capping layer on a first surface of the reference electrode membrane, wherein the capping layer comprises cellulose acetate.

[0108] Clause 11. A method of making a reference electrode membrane, comprising:

[0109] providing a solution comprising one or more conductive salts, one or more polyurethanes, and one or more solvents,

[0110] providing the solution on a surface, and

[0111] drying the solution to provide a reference electrode membrane.

[0112] Clause 12. The method according to clause 11, wherein the one or more solvents comprise tetrahydrofuran, dimethyl sulfate, methanol, ethanol, cyclohexanone, dimethylacetamide, or a combination thereof.

[0113] Clause 13. A method of making a reference electrode, comprising:

[0114] providing a solution comprising one or more conductive salts, one or more polyurethanes, and one or more solvents,

[0115] providing the solution on a surface of a contact electrode, and

[0116] drying the solution to provide a reference electrode membrane on the contact electrode.

[0117] Clause 14. The method according to clause 13, wherein the contact electrode comprises an electrical conductor selected from silver, silver chloride, silver bromide, silver iodide, gold, platinum, copper, aluminum, and combinations thereof.

[0118] Clause 15. The method according to clause 13, further comprising:

[0119] providing a capping solution comprising one or more capping agents,

[0120] providing the capping solution on a first surface of the reference electrode membrane, and

[0121] drying the capping solution to provide a capping layer on the first surface of the reference electrode membrane.

[0122] Clause 16. The method according to clause 15, wherein the one or more capping agents comprise cellulose acetate.

[0123] Clause 17. A reference electrode membrane, comprising:

[0124] one or more one or more polypropylenes, and

[0125] one or more conductive salts.

[0126] Clause 18. The reference electrode membrane according to clause 17, further comprising one or more polymeric resin components.

[0127] Clause 19. The reference electrode membrane according to clause 18, wherein the one or more polymeric resin components comprise one or more polyvinyl-based materials.

[0128] Clause 20. The reference electrode membrane according to clause 17, wherein the one or more conductive salts comprise a chloride salt.

[0129] Clause 21. The reference electrode membrane according to clause 17, further comprising one or more conductive materials comprising one or more metals, one or more conductive carbon-containing materials, one or more conductive polymers, or a combination thereof.

[0130] Clause 22. A reference electrode, comprising:

[0131] a contact electrode having the reference electrode membrane according to clause 17 on a surface thereof.

[0132] Clause 23. The reference electrode according to clause 22, wherein the contact electrode comprises an electrical conductor selected from silver, silver chloride, silver bromide, silver iodide, gold, platinum, copper, aluminum, and combinations thereof.

[0133] Clause 24. The reference electrode according to clause 22, further comprising a capping layer on a first surface of the reference electrode membrane, wherein the capping layer comprises cellulose acetate.

[0134] Clause 25. A method of making a reference electrode membrane, comprising:

[0135] providing a solution comprising one or more conductive salts, one or more one or more polypropylenes, and one or more solvents,

[0136] providing the solution on a surface, and

[0137] drying the solution to provide a reference electrode membrane.

[0138] Clause 26. The method according to clause 25, wherein the one or more solvents comprise tetrahydrofuran, dimethyl sulfate, methanol, ethanol, cyclohexanone, dimethylacetamide, or a combination thereof.

[0139] Clause 27. A method of making a reference electrode, comprising:

[0140] providing a solution comprising one or more conductive salts, one or more one or more polypropylenes, and one or more solvents,

[0141] providing the solution on a surface of a contact electrode, and

[0142] drying the solution to provide a reference electrode membrane on the contact electrode.

[0143] Clause 28. The method according to clause 27, wherein the contact electrode comprises an electrical conductor selected from silver, silver chloride, silver bromide, silver iodide, gold, platinum, copper, aluminum, and combinations thereof.

[0144] Clause 29. The method according to clause 27, further comprising:

[0145] providing a capping solution comprising one or more capping agents,

[0146] providing the capping solution on a first surface of the reference electrode membrane, and

[0147] drying the capping solution to provide a capping layer on the first surface of the reference electrode membrane.

[0148] Clause 30. The method according to clause 29, wherein the one or more capping agents comprise cellulose acetate.

[0149] Clause 31. A reference electrode membrane, comprising:

[0150] one or more cellulose materials, and

[0151] one or more conductive salts.

[0152] Clause 32. The reference electrode membrane according to clause 31, further comprising one or more polymeric resin components.

[0153] Clause 33. The reference electrode membrane according to clause 32, wherein the one or more polymeric resin components comprise one or more polyvinyl-based materials.

[0154] Clause 34. The reference electrode membrane according to clause 31, wherein the one or more conductive salts comprise a chloride salt.

[0155] Clause 35. The reference electrode membrane according to clause 31, further comprising one or more conductive materials comprising one or more metals, one or more conductive carbon-containing materials, one or more conductive polymers, or a combination thereof.

[0156] Clause 36. A reference electrode, comprising:

[0157] a contact electrode having the reference electrode membrane according to clause 31 on a surface thereof.

[0158] Clause 37. The reference electrode according to clause 36, wherein the contact electrode comprises an electrical conductor selected from silver, silver chloride, silver bromide, silver iodide, gold, platinum, copper, aluminum, and combinations thereof.

[0159] Clause 38. The reference electrode according to clause 36, further comprising a capping layer on a first surface of the reference electrode membrane, wherein the capping layer comprises cellulose acetate.

[0160] Clause 39. A method of making a reference electrode membrane, comprising:

[0161] providing a solution comprising one or more conductive salts, one or more cellulose materials, and one or more solvents,

[0162] providing the solution on a surface, and

[0163] drying the solution to provide a reference electrode membrane.

[0164] Clause 40. The method according to clause 39, wherein the one or more solvents comprise tetrahydrofuran, dimethyl sulfate, methanol, ethanol, cyclohexanone, dimethylacetamide, or a combination thereof.

[0165] Clause 41. A method of making a reference electrode, comprising:

[0166] providing a solution comprising one or more conductive salts, one or more cellulose materials, and one or more solvents,

[0167] providing the solution on a surface of a contact electrode, and

[0168] drying the solution to provide a reference electrode membrane on the contact electrode.

[0169] Clause 42. The method according to clause 41, wherein the contact electrode comprises an electrical conductor selected from silver, silver chloride, silver bromide, silver iodide, gold, platinum, copper, aluminum, and combinations thereof.

[0170] Clause 43. The method according to clause 41, further comprising:

[0171] providing a capping solution comprising one or more capping agents,

[0172] providing the capping solution on a first surface of the reference electrode membrane, and

[0173] drying the capping solution to provide a capping layer on the first surface of the reference electrode membrane.

[0174] Clause 44. The method according to clause 43, wherein the one or more capping agents comprise cellulose acetate.

[0175] Clause 45. A reference electrode comprising:

[0176] a contact electrode having a reference electrode membrane on a surface thereof, wherein the reference electrode membrane comprises one or more conductive salts, and

[0177] a capping layer on a first surface of the reference electrode membrane, wherein the capping layer comprises cellulose acetate, one or more polyurethanes, or a combination thereof.

[0178] Clause 46. The reference electrode according to clause 45, wherein the reference electrode membrane further comprises one or more conductive materials comprising one or more metals, one or more conductive carbon-containing materials, one or more conductive polymers, or a combination thereof.EXAMPLES

[0179] EXAMPLE I: Preparation of Reference Electrodes

[0180] First, two solutions containing at least one conductive salt, at least one polyurethane, at least one polymeric resin component, and a solvent were prepared as shown in Table 1.Table 1

[0181] Enough of each solution from Tables 1 was then provided to fill each of two cavities formed in an insulated substrate with a conductive bottom surface and allowed to dry at room temperature to provide two total inventive reference electrodes each having an inventive reference electrode membrane.

[0182] EXAMPLE II: Analysis of Reference Electrodes

[0183] The performance of the inventive reference electrodes prepared according to Example I were analyzed by exposing the inventive reference electrodes to calibration solutions containing various chloride concentrations (i.e., 80 mM, 110 mM, 143 mM, and 160 mM) and comparing the results with those of a cove Ag / AgCl reference electrode as shown in FIG. 4 and as described in U.S. Patent Publication No. 2023 / 0358701, the contents of which are incorporated herein in their entirety by reference. In particular, FIG. 4 shows a sensing assembly 400 having a plurality of working electrodes 401 provided in a primary fluid channel 402, and a reference electrode element 403 (i.e., the cove Ag / AgCl reference electrode) in a secondary fluid channel 404 having a reference electrolyte solution as shown.

[0184] Table 2 provides the chloride sensitivity measured over several days for each reference electrode. It should be understood that lower chloride sensitivity implies greater voltage stability during chloride concentration fluctuations. These results show that the inventive reference electrode membranes of the present disclosure exceed the performance and stability of the cove Ag / AgCl reference electrode with reference solution.Table 2

[0185] FIGS. 5A-5F show the linear sensitivity plots corresponding with Table 2. In particular, FIGS. 5A-5F show the sensitivity of the inventive reference electrodes over seven days, with sensor output in microvolts along the y-axis and time along the x-axis. As shown, all of the inventive reference electrodes performed within the accepted range for all tests. In addition, inventive reference electrodes RE-G-1M and RE-G-1D showed significantly less interference from chloride ions than the interference observed in the cove Ag / AgCl reference electrode.

[0186] EXAMPLE III: Analysis of Reference Electrodes

[0187] The analysis described in Example II was repeated using calibration solutions containing 10 mM bromide or 2 mM iodide. In addition, one control reference electrode membrane without polyurethane as shown in Table 3 was analyzed.Table 3

[0188] FIGS. 6A-6C show the results of this study. In particular, the y-axis of the graphs in FIGS. 6A-6C is the change in voltage (in microvolts) observed for each reference electrode due to the addition of either bromide or iodide as described above. As shown in FIGS. 6A-6C, the interference effect is greatest for the control reference electrode (i.e., RE-B), whereas the inventive reference electrodes significantly reduced interference of both bromide and iodide ions, reaching levels similar to the reference electrode membrane with reference solution (i.e., “cove”). It was thus determined that the inventive reference electrodes are capable of providing a significantly simplified sensor in terms ofminiaturization (e.g., no need for a secondary channel) and potential issues with mixing of solutions between the “sample channel” and the secondary reference electrode “cove” channel

[0189] EXAMPLE IV: Analysis of Reference Electrodes

[0190] The performance of three inventive reference electrode membranes formed from RE-G-1M as described in Example I (referred to as RE-01, RE-02, and RE-03) were analyzed over two days. In particular, five ion selective electrode membranes (E3-E7) were exposed to a calibration solution having different concentrations of target ions (i.e., 0.2 mM, 0.5 mM, 0.9 mM, 1.16 mM, and 1.8 mM) and sample voltage steps were recorded using the three inventive reference electrode membranes RE-01, RE-02, and RE-03 and a standard external reference electrode. Table 4 shows the sensitivities measured for target selective electrode membranes E3-E7 using each reference electrode type.Table 4

[0191] FIGS. 7A-7D show the linear sensitivity plots corresponding with Table 4 with sensor output in microvolts along the y-axis and time along the x-axis. These results show that the chloride selective electrode membrane performance using inventive reference electrodes matched the performance with a standard reference electrode.

[0192] EXAMPLE V: Analysis of Reference Electrodes

[0193] First, a solution containing at least one conductive salt, at least one polyurethane, at least one polymeric resin component, at least one conductive material, and a solvent were prepared as shown in Table 1.Table 5

[0194] Enough solution from Tables 5 was then provided to fill a cavity formed in an insulated substrate with a conductive bottom surface and allowed to dry at room temperature to provide an inventive reference electrode having an inventive reference electrode membrane.

[0195] The performance of the electrode was then analyzed over three days and compared with the cove Ag / AgCl reference electrode as described in Example II. FIGS. 8 A and 8B show the linear sensitivity plots corresponding with the sensor outputs in microvolts along the y-axis and time along the x-axis. These results show that the conductive material particles (i.e., the silver paste) reduced the membrane impedance, which is especially advantageous in measurement electronics.

[0196] Further examples of the reference electrode membranes, reference electrodes and methods disclosed herein are provided as clauses:

[0197] Clause 1. A reference electrode membrane, comprising: one or more conductive salts, and one or more polyurethanes.

[0198] Clause 2. The reference electrode membrane according to clause 1, further comprising one or more polymeric resin components.

[0199] Clause 3. The reference electrode membrane according to clause 2, wherein the one or more polymeric resin components comprise one or more polyvinyl-based materials.

[0200] Clause 4. The reference electrode membrane according to any of clauses 1 to 3, wherein the one or more conductive salts comprise a chloride salt.

[0201] Clause 5. The reference electrode membrane according to any of clauses 1 to 4, wherein the one or more polyurethanes comprise a polyurethane having one or more hydrophobic functional groups.

[0202] Clause 6. The reference electrode membrane according to any of clauses 1 to 5, wherein the one or more polyurethanes comprise a polyurethane having one or more hydrophilic functional groups.

[0203] Clause 7. The reference electrode membrane according to any of clauses 1 to 6, further comprising one or more conductive materials comprising one or more metals, one or more conductive carbon-containing materials, one or more conductive polymers, or a combination thereof.

[0204] Clause 8. A reference electrode, comprising: a contact electrode having the reference electrode membrane according to any of clauses 1 to 7 on a surface thereof.

[0205] Clause 9. The reference electrode according to clause 8, wherein the contact electrode comprises an electrical conductor selected from silver, silver chloride, silver bromide, silver iodide, gold, platinum, copper, aluminum, and combinations thereof.

[0206] Clause 10. The reference electrode according to clause 8 or clause 9, further comprising a capping layer on a first surface of the reference electrode membrane, wherein the capping layer comprises cellulose acetate.

[0207] Clause 11. A method of making a reference electrode membrane, comprising: providing a solution comprising one or more conductive salts, one or more polyurethanes, and one or more solvents, providing the solution on a surface, and drying the solution to provide a reference electrode membrane.

[0208] Clause 12. The method according to clause 11, wherein the one or more solvents comprise tetrahydrofuran, dimethyl sulfate, methanol, ethanol, cyclohexanone, dimethylacetamide, or a combination thereof.

[0209] Clause 13. A method of making a reference electrode, comprising: providing a solution comprising one or more conductive salts, one or more polyurethanes, and one ormore solvents, providing the solution on a surface of a contact electrode, and drying the solution to provide a reference electrode membrane on the contact electrode.

[0210] Clause 14. The method according to clause 13, wherein the contact electrode comprises an electrical conductor selected from silver, silver chloride, silver bromide, silver iodide, gold, platinum, copper, aluminum, and combinations thereof.

[0211] Clause 15. The method according to clause 13 or clause 14, further comprising: providing a capping solution comprising one or more capping agents, providing the capping solution on a first surface of the reference electrode membrane, and drying the capping solution to provide a capping layer on the first surface of the reference electrode membrane.

[0212] Clause 16. The method according to clause 15, wherein the one or more capping agents comprise cellulose acetate.

[0213] Clause 17. A reference electrode membrane, comprising: one or more polypropylenes, and one or more conductive salts.

[0214] Clause 18. The reference electrode membrane according to clause 17, further comprising one or more polymeric resin components.

[0215] Clause 19. The reference electrode membrane according to clause 18, wherein the one or more polymeric resin components comprise one or more polyvinyl-based materials.

[0216] Clause 20. The reference electrode membrane according to any of clauses 17 to 19, wherein the one or more conductive salts comprise a chloride salt.

[0217] Clause 21. The reference electrode membrane according to any of clauses 17 to 20, further comprising one or more conductive materials comprising one or more metals, one or more conductive carbon-containing materials, one or more conductive polymers, or a combination thereof.

[0218] Clause 22. A reference electrode, comprising: a contact electrode having the reference electrode membrane according to any of clauses 17 to 21 on a surface thereof.

[0219] Clause 23. The reference electrode according to clause 22, wherein the contact electrode comprises an electrical conductor selected from silver, silver chloride, silver bromide, silver iodide, gold, platinum, copper, aluminum, and combinations thereof.

[0220] Clause 24. The reference electrode according to clause 22 or clause 23, further comprising a capping layer on a first surface of the reference electrode membrane, wherein the capping layer comprises cellulose acetate.

[0221] Clause 25. A method of making a reference electrode membrane, comprising: providing a solution comprising one or more conductive salts, one or more one or more polypropylenes, and one or more solvents, providing the solution on a surface, and drying the solution to provide a reference electrode membrane.

[0222] Clause 26. The method according to clause 25, wherein the one or more solvents comprise tetrahydrofuran, dimethyl sulfate, methanol, ethanol, cyclohexanone, dimethylacetamide, or a combination thereof.

[0223] Clause 27. A method of making a reference electrode, comprising: providing a solution comprising one or more conductive salts, one or more one or more polypropylenes, and one or more solvents, providing the solution on a surface of a contact electrode, and drying the solution to provide a reference electrode membrane on the contact electrode.

[0224] Clause 28. The method according to clause 27, wherein the contact electrode comprises an electrical conductor selected from silver, silver chloride, silver bromide, silver iodide, gold, platinum, copper, aluminum, and combinations thereof.

[0225] Clause 29. The method according to clause 27 or clause 28, further comprising: providing a capping solution comprising one or more capping agents, providing the capping solution on a first surface of the reference electrode membrane, and drying the capping solution to provide a capping layer on the first surface of the reference electrode membrane.

[0226] Clause 30. The method according to clause 29, wherein the one or more capping agents comprise cellulose acetate.

[0227] Clause 31. A reference electrode membrane, comprising: one or more cellulose materials, and one or more conductive salts.

[0228] Clause 32. The reference electrode membrane according to clause 31, further comprising one or more polymeric resin components.

[0229] Clause 33. The reference electrode membrane according to clause 32, wherein the one or more polymeric resin components comprise one or more polyvinyl-based materials.

[0230] Clause 34. The reference electrode membrane according to any of clauses 31 to 33, wherein the one or more conductive salts comprise a chloride salt.

[0231] Clause 35. The reference electrode membrane according to any of clauses 31 to 34, further comprising one or more conductive materials comprising one or more metals, one or more conductive carbon-containing materials, one or more conductive polymers, or a combination thereof.

[0232] Clause 36. A reference electrode, comprising: a contact electrode having the reference electrode membrane according to any of clauses 31 to 35 on a surface thereof.

[0233] Clause 37. The reference electrode according to clause 36, wherein the contact electrode comprises an electrical conductor selected from silver, silver chloride, silver bromide, silver iodide, gold, platinum, copper, aluminum, and combinations thereof.

[0234] Clause 38. The reference electrode according to clause 36 or clause 37, further comprising a capping layer on a first surface of the reference electrode membrane, wherein the capping layer comprises cellulose acetate.

[0235] Clause 39. A method of making a reference electrode membrane, comprising: providing a solution comprising one or more conductive salts, one or more cellulose materials, and one or more solvents, providing the solution on a surface, and drying the solution to provide a reference electrode membrane.

[0236] Clause 40. The method according to clause 39, wherein the one or more solvents comprise tetrahydrofuran, dimethyl sulfate, methanol, ethanol, cyclohexanone, dimethylacetamide, or a combination thereof.

[0237] Clause 41. A method of making a reference electrode, comprising: providing a solution comprising one or more conductive salts, one or more cellulose materials, and one or more solvents, providing the solution on a surface of a contact electrode, and drying the solution to provide a reference electrode membrane on the contact electrode.

[0238] Clause 42. The method according to clause 41, wherein the contact electrode comprises an electrical conductor selected from silver, silver chloride, silver bromide, silver iodide, gold, platinum, copper, aluminum, and combinations thereof.

[0239] Clause 43. The method according to clause 41 or clause 42, further comprising: providing a capping solution comprising one or more capping agents, providing the capping solution on a first surface of the reference electrode membrane, and drying the capping solution to provide a capping layer on the first surface of the reference electrode membrane.

[0240] Clause 44. The method according to clause 43, wherein the one or more capping agents comprise cellulose acetate.

[0241] Clause 45. A reference electrode comprising: a contact electrode having a reference electrode membrane on a surface thereof, wherein the reference electrode membrane comprises one or more conductive salts, and a capping layer on a first surface of the reference electrode membrane, wherein the capping layer comprises cellulose acetate, one or more polyurethanes, or a combination thereof.

[0242] Clause 46. The reference electrode according to clause 45, wherein the reference electrode membrane further comprises one or more conductive materials comprising one or more metals, one or more conductive carbon-containing materials, one or more conductive polymers, or a combination thereof.

Claims

AMENDED CLAIMS received by the International Bureau on 02 April 2026 (02.04.2026)

1. A reference electrode membrane, comprising: one or more conductive salts, and one or more polyurethanes, comprising a polyurethane having one or more hydrophobic functional groups.

2. The reference electrode membrane according to claim 1, further comprising one or more polymeric resin components.

3. The reference electrode membrane according to claim 2, wherein the one or more polymeric resin components comprise one or more polyvinyl-based materials.

4. The reference electrode membrane according to claim 1, wherein the one or more conductive salts comprise a chloride salt.

5. (Cancelled)

6. The reference electrode membrane according to claim 1, wherein the one or more polyurethanes comprise a polyurethane having one or more hydrophilic functional groups.

7. The reference electrode membrane according to claim 1, further comprising one or more conductive materials comprising one or more metals, one or more conductive carbon-containing materials, one or more conductive polymers, or a combination thereof.

8. A reference electrode, comprising: a contact electrode having the reference electrode membrane according to claim 1 on a surface thereof.

9. The reference electrode according to claim 8, wherein the contact electrode comprises an electrical conductor selected from silver, silver chloride, silver bromide, silver iodide, gold, platinum, copper, aluminum, and combinations thereof.

10. The reference electrode according to claim 8, further comprising a capping layer on a first surface of the reference electrode membrane, wherein the capping layer comprises cellulose acetate.

11. A method of making a reference electrode membrane, comprising: providing a solution comprising one or more conductive salts, one or more polyurethanes, and one or more solvents, wherein the one or more polyurethanes comprise a polyurethane having one or more hydrophobic functional groups, providing the solution on a surface, and drying the solution to provide a reference electrode membrane.

12. The method according to claim 11, wherein the one or more solvents comprise tetrahydrofuran, dimethyl sulfate, methanol, ethanol, cyclohexanone, dimethylacetamide, or a combination thereof.

13. A method of making a reference electrode, comprising: providing a solution comprising one or more conductive salts, one or more polyurethanes, and one or more solvents, wherein the one or more polyurethanes comprise a polyurethane having one or more hydrophobic functional groups, providing the solution on a surface of a contact electrode, and drying the solution to provide a reference electrode membrane on the contact electrode.

14. The method according to claim 13, wherein the contact electrode comprises an electrical conductor selected from silver, silver chloride, silver bromide, silver iodide, gold, platinum, copper, aluminum, and combinations thereof.

15. The method according to claim 13, further comprising: providing a capping solution comprising one or more capping agents, providing the capping solution on a first surface of the reference electrode membrane, and drying the capping solution to provide a capping layer on the first surface of the reference electrode membrane.

16. The method according to claim 15, wherein the one or more capping agents comprise cellulose acetate.

17. A reference electrode membrane, comprising: one or more polypropylenes, and one or more conductive salts.

18. The reference electrode membrane according to claim 17, further comprising one or more polymeric resin components.

19. The reference electrode membrane according to claim 18, wherein the one or more polymeric resin components comprise one or more polyvinyl-based materials.

20. The reference electrode membrane according to claim 17, wherein the one or more conductive salts comprise a chloride salt.

21. The reference electrode membrane according to claim 17, further comprising one or more conductive materials comprising one or more metals, one or more conductive carbon-containing materials, one or more conductive polymers, or a combination thereof.

22. A reference electrode, comprising:a contact electrode having the reference electrode membrane according to claim 17 on a surface thereof.

23. The reference electrode according to claim 22, wherein the contact electrode comprises an electrical conductor selected from silver, silver chloride, silver bromide, silver iodide, gold, platinum, copper, aluminum, and combinations thereof.

24. The reference electrode according to claim 22, further comprising a capping layer on a first surface of the reference electrode membrane, wherein the capping layer comprises cellulose acetate.

25. A method of making a reference electrode membrane, comprising: providing a solution comprising one or more conductive salts, one or more one or more polypropylenes, and one or more solvents, providing the solution on a surface, and drying the solution to provide a reference electrode membrane.

26. The method according to claim 25, wherein the one or more solvents comprise tetrahydrofuran, dimethyl sulfate, methanol, ethanol, cyclohexanone, dimethylacetamide, or a combination thereof.

27. A method of making a reference electrode, comprising: providing a solution comprising one or more conductive salts, one or more one or more polypropylenes, and one or more solvents, providing the solution on a surface of a contact electrode, and drying the solution to provide a reference electrode membrane on the contact electrode.

28. The method according to claim 27, wherein the contact electrode comprises an electrical conductor selected from silver, silver chloride, silver bromide, silver iodide, gold, platinum, copper, aluminum, and combinations thereof.

29. The method according to claim 27, further comprising: providing a capping solution comprising one or more capping agents, providing the capping solution on a first surface of the reference electrode membrane, and drying the capping solution to provide a capping layer on the first surface of the reference electrode membrane.

30. The method according to claim 29, wherein the one or more capping agents comprise cellulose acetate.

31. A reference electrode membrane, comprising: one or more cellulose materials, and one or more conductive salts.

32. The reference electrode membrane according to claim 31, further comprising one or more polymeric resin components.

33. The reference electrode membrane according to claim 32, wherein the one or more polymeric resin components comprise one or more polyvinyl-based materials.

34. The reference electrode membrane according to claim 31, wherein the one or more conductive salts comprise a chloride salt.

35. The reference electrode membrane according to claim 31, further comprising one or more conductive materials comprising one or more metals, one or more conductive carbon-containing materials, one or more conductive polymers, or a combination thereof.

36. A reference electrode, comprising: a contact electrode having the reference electrode membrane according to claim 31 on a surface thereof.

37. The reference electrode according to claim 36, wherein the contact electrode comprises an electrical conductor selected from silver, silver chloride, silver bromide, silver iodide, gold, platinum, copper, aluminum, and combinations thereof.

38. The reference electrode according to claim 36, further comprising a capping layer on a first surface of the reference electrode membrane, wherein the capping layer comprises cellulose acetate.

39. A method of making a reference electrode membrane, comprising: providing a solution comprising one or more conductive salts, one or more cellulose materials, and one or more solvents, providing the solution on a surface, and drying the solution to provide a reference electrode membrane.

40. The method according to claim 39, wherein the one or more solvents comprise tetrahydrofuran, dimethyl sulfate, methanol, ethanol, cyclohexanone, dimethylacetamide, or a combination thereof.

41. A method of making a reference electrode, comprising: providing a solution comprising one or more conductive salts, one or more cellulose materials, and one or more solvents, providing the solution on a surface of a contact electrode, and drying the solution to provide a reference electrode membrane on the contact electrode.

42. The method according to claim 41, wherein the contact electrode comprises an electrical conductor selected from silver, silver chloride,silver bromide, silver iodide, gold, platinum, copper, aluminum, and combinations thereof.

43. The method according to claim 41, further comprising: providing a capping solution comprising one or more capping agents, providing the capping solution on a first surface of the reference electrode membrane, and drying the capping solution to provide a capping layer on the first surface of the reference electrode membrane.

44. The method according to claim 43, wherein the one or more capping agents comprise cellulose acetate.

45. A reference electrode comprising: a contact electrode having a reference electrode membrane on a surface thereof, wherein the reference electrode membrane comprises one or more conductive salts, and a capping layer on a first surface of the reference electrode membrane, wherein the capping layer comprises cellulose acetate, one or more polyurethanes, or a combination thereof.

46. The reference electrode according to claim 45, wherein the reference electrode membrane further comprises one or more conductive materials comprising one or more metals, one or more conductive carbon-containing materials, one or more conductive polymers, or a combination thereof.[0001][0002]Statement under Article 19(1) PCT[0003]Statement explaining the amendment[0004]Claim 1 has been amended to recite “comprising a polyurethane having one or more hydrophobic functional groups”.[0005]Claim 11 has been amended to recite “wherein the one or more polyurethanes comprise a polyurethane having one or more hydrophobic functional groups”.[0006]Claim 13 has been amended to recite “wherein the one or more polyurethanes comprise a polyurethane having one or more hydrophobic functional groups”.[0007]Claim 5 has been cancelled.[0008]Claims 2-4, 6-10, 12, 14-46 remain unchanged.[0009]45

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