# US 9,518,952 B2 · Gas sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,518,952 B2 - Document ID: US9518952B2 - Status: Granted - Kind: B2 - Application number: 14/349,905 - Filed: 2011-10-05 - Published: 2014-09-11 - Granted: 2016-12-13 - Earliest claimed: 2011-10-05 - Assignees: UTC Fire & Security Corporation - Applicants: Lei Chen; Zhiwei Yang; Jean Yamanis; Georgios S. Zafiris; Joseph J. Sangiovanni - Inventors: Lei Chen; Zhiwei Yang; Jean Yamanis; Georgios S. Zafiris; Joseph J. Sangiovanni - Web page: https://patentgrep.com/patent/US9518952B2 ## CPC - G01N 27/407: for investigating or analysing gases {(G01N27/411 takes precedence)} - G01N 27/40: Semi-permeable membranes or partitions - G01N 27/404: Cells with anode, cathode and cell electrolyte on the same side of a permeable membrane which separates them from the sample fluid {, e.g. Clark-type oxygen sensors} - G01N 27/4074: {for detection of gases other than oxygen} - G01N 27/413: Concentration cells using liquid electrolytes {measuring currents or voltages in voltaic cells} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract A membrane electrode assembly for a gas sensor is described that includes a membrane disposed between a sensing electrode and a counter electrode. The membrane is a polymer membrane, such as an ionomer, having an ionic liquid retained therein. ## Claims ### Claim 1 A membrane electrode assembly for a gas sensor, comprising: a sensing electrode; a counter electrode; and a polymer membrane comprising an ionomer, disposed between the sensing electrode and the counter electrode, the polymer membrane comprising an ionic liquid retained therein. ### Claim 2 (depends on 1) The assembly of claim 1, wherein the ionomer has a molecular structure that comprises a hydrophobic portion and a hydrophilic portion. ### Claim 3 (depends on 2) The assembly of claim 2, wherein the hydrophobic portion comprises a fluoropolymer repeat unit. ### Claim 4 (depends on 3) The assembly of claim 3, wherein the fluoropolymer comprises tetrafluoroethylene repeat units. ### Claim 5 (depends on 2) The assembly of claim 2, wherein the hydrophilic portion comprises a sulfonic acid group, a phosphonic acid group, or a sulfonamide acid group. ### Claim 6 (depends on 5) The assembly of claim 5, wherein the sulfonic acid group is a sulfonic acid group-terminated perfluorovinyl ether group. ### Claim 7 (depends on 1) The assembly of claim 1, wherein the ionic liquid has at least one complex grafted to the polymer. ### Claim 8 (depends on 1) The assembly of claim 1, wherein the ionic liquid comprises an imidazolium, pyridinium, tetralkylammonium, pyrrolidinium, trialkylsulfonium, pyrazolium, triazolium, thiazolium, oxazolium, pyridazinium, pyrimidinium, or pyrazinium cation. ### Claim 9 (depends on 8) The assembly of claim 8, wherein the ionic liquid comprises one or more anions selected from the group consisting of Cl, Br, BF4, PF6, AlCl4, SCN, HSO4, HCO3, CH3SO3, CH3CH2SO4, (CH3(CH2)3O)2POO, (CF3SO2)2N, dicyanamide, CF3SO3, (CF3CF2S02)2N, L-(+)-lactate, CH3SO4, and CH3COO. ### Claim 10 (depends on 1) The assembly of claim 1, wherein the ionic liquid comprises one or more cations according to the formula: wherein R and R1 are independently H, substituted or unsubstituted alkyl of 1 to 30 carbon atoms, or substituted or unsubstituted aryl of 6 to 30 carbon atoms; and X is an anion. ### Claim 11 (depends on 10) The assembly of claim 10, wherein R is selected from the group consisting of —(CH2)3CH3, —CH2CH3, —CH3, —CH═CH2, —CH2CN, and —(CH2)3CN, and R1 is selected from the group consisting of H, —CH3, —CH2CN, and —(CH2)3CN. ### Claim 12 (depends on 1) The assembly of claim 1, wherein either or both of the sensing electrode has an ionic liquid retained within the electrode. ### Claim 13 (depends on 1) The assembly of claim 1, wherein the membrane is a proton exchange membrane. ### Claim 14 A membrane electrode assembly for a gas sensor, comprising a sensing electrode; a counter electrode; and a polymer membrane disposed between the sensing electrode and the counter electrode, the polymer membrane comprising an ionic liquid retained therein, wherein either or both of the sensing electrode and the reference electrode comprises carbon particles, an ionomer, an ionic liquid retained within the electrode, and optionally a catalyst. ### Claim 15 A gas sensor comprising a housing having disposed therein a membrane electrode assembly comprising: a sensing electrode; a counter electrode; and a polymer membrane comprising an ionomer, disposed between the sensing electrode and the counter electrode, the polymer membrane comprising an ionic liquid retained therein; said housing containing a reference gas chamber to which the counter electrode is exposed, and a test gas chamber to which the sensing electrode is disposed; a pathway for test gas to enter the test gas chamber; and an electrical circuit connecting the sensing electrode and the counter electrode. ### Claim 16 (depends on 15) The gas sensor of claim 15 wherein the test gas is carbon monoxide. ### Claim 17 (depends on 16) The gas sensor of claim 16, the sensor being free of a liquid water reservoir. ### Claim 18 (depends on 15) A method of using the sensor of claim 15, comprising generating a difference in electronegative potential between the sensing electrode and the counter electrode that is responsive to the presence and/or concentration of a component in a gas being tested, measuring voltage or current in said electrical circuit, and converting the measured voltage or current to a reading indicative of the presence and/or concentration of the component in the gas being tested. ### Claim 19 (depends on 18) The method of claim 18, further comprising adjusting the conversion of measured voltage or current to the reading based on humidity. ### Claim 20 (depends on 19) The method of claim 19, wherein the humidity is determined based on the impedance or conductivity of the electrode assembly.