Gas sensors and methods of sensing a gas-phase analyte
Gas sensors are provided. The gas sensors comprise: a substrate; a plurality of electrodes on the substrate; and a polymeric sensing layer on the substrate for adsorbing a gas-phase analyte. The adsorption of the analyte is effective to change a property of the gas sensor that results in a change in an output signal from the gas sensor. The polymeric sensing layer comprises a polymer chosen from substituted or unsubstituted polyarylenes comprising the reaction product of monomers comprising a first monomer comprising an aromatic acetylene group and a second monomer comprising two or more cyclopentadienone groups, or a cured product of the reaction product. The gas sensors and methods of using such sensors find particular applicability in the sensing of gas-phase organic analytes.
1. A gas sensor, comprising:
a substrate;
a plurality of electrodes on the substrate; and
a polymeric sensing layer on the substrate for adsorbing a gas-phase analyte, the adsorption of which analyte is effective to change a property of the gas sensor that results in a change in an output signal from the gas sensor, wherein the polymeric sensing layer comprises a polymer chosen from substituted or unsubstituted polyarylenes comprising the reaction product of monomers comprising a first monomer comprising an aromatic acetylene group and a second monomer comprising two or more cyclopentadienone groups, or a cured product of the reaction product, wherein the first monomer is chosen from monomers of formula (1) or formula (2):
wherein: R is independently chosen from H, —C(═O)OR 2 , substituted or unsubstituted C 6-20 aryl, or substituted or unsubstituted C 4-20 heteroaryl; R 1 is independently chosen from F, substituted or unsubstituted C 1-10 alkyl, substituted or unsubstituted C 6-20 aryl, C 4-20 heteroaryl, —C≡C—R, —C(═O)OR 2 , —C(═O)NHR 3 , —O—C(═O)R 4 , —NHC(═O)R 5 ,— S(═O) 2 —OR 6 , or S(═O) 2 —NHR 3 ; R 2 is independently chosen from H, substituted or unsubstituted C 1-10 alkyl, C 6-20 aryl, or C 4-20 heteroaryl; R 3 is independently chosen from H or substituted or unsubstituted C 1-10 alkyl; R 4 is independently chosen from H or substituted or unsubstituted C 1-10 alkyl; R 5 is independently chosen from H or substituted or unsubstituted C 1-10 alkyl; R 6 is independently chosen from H or substituted or unsubstituted C 1-10 alkyl; and a in formula (1) is an integer from 0 to 2, and a in formula (2) is an integer from 0 to 3; and the second monomer is of formula (3A):
wherein each R 7 is independently chosen from H, substituted or unsubstituted C 1-6 alkyl, substituted or unsubstituted C 6-20 aryl, or substituted or unsubstituted C 4-20 heteroaryl; R 8 is substituted or unsubstituted C 6-20 aryl, or substituted or unsubstituted C 4-20 heteroaryl; R 9 is independently chosen from substituted or unsubstituted C 1-6 alkyl, substituted or unsubstituted C 6-20 aryl, or substituted or unsubstituted C 4-20 heteroaryl; and Ar 1 is an aromatic moiety.
2. The gas sensor of claim 1 , wherein the polymer exhibits an FTIR spectroscopy spectrum having a ratio of total peak area from 1648 to 1690 cm −1 to total peak area from 1480 to 1522 cm +1 of 0.15 or less.
3. The gas sensor of claim 2 , wherein the polymeric sensing layer exhibits a Raman spectroscopy spectrum having a ratio of total peak area from 2190 to 2250 cm −1 to total peak area from 1550 to 1650 cm −1 of 1.0 or less.
4. The gas sensor of claim 1 , wherein the polymeric sensing layer has an oxygen content of 7 atomic % or less as measured by x-ray photoelectron spectroscopy.
5. The gas sensor of claim 1 , wherein the polymeric sensing layer is formed by a process comprising coating a composition comprising the first monomer, the second monomer and a solvent, and curing the coated composition at a temperature of from 300 to 400° in an inert gas atmosphere.
6. The gas sensor of claim 1 , wherein the gas sensor is an acoustic wave, capacitive, or conductometric gas sensor.
7. The gas sensor of claim 6 , wherein the gas sensor is an acoustic wave gas sensor.
8. A method of sensing a gas-phase analyte, comprising:
(a) providing a gas sensor, comprising:
a substrate;
a plurality of electrodes on the substrate; and
a polymeric sensing layer on the substrate for adsorbing a gas-phase analyte, the adsorption of which analyte is effective to change a property of the gas sensor that results in a change in an output signal from the gas sensor, wherein the polymeric sensing layer comprises a polymer chosen from substituted or unsubstituted polyarylenes comprising the reaction product of monomers comprising a first monomer comprising an aromatic acetylene group and a second monomer comprising two or more cyclopentadienone groups, or a cured product of the reaction product, wherein the first monomer is chosen from monomers of formula (1) or formula (2):
wherein: R is independently chosen from H, —C(═O)OR 2 , substituted or unsubstituted C 6-20 aryl, or substituted or unsubstituted C 4-20 heteroaryl; R 1 is independently chosen from F, substituted or unsubstituted C 1-10 alkyl, substituted or unsubstituted C 6-20 aryl, C 4-20 heteroaryl, —C≡C—R, —C(═O)OR 2 , —C(═O)NHR 3 , —O—C(═O)R 4 , —NHC(═O)R 5 ,—S(═O) 2 —OR 6 , or S(═O) 2 —NHR 3 ; R 2 is independently chosen from H, substituted or unsubstituted C 1-10 alkyl, C 6-20 aryl, or C 4-20 heteroaryl; R 3 is independently chosen from H or substituted or unsubstituted C 1-10 alkyl; R 4 is independently chosen from H or substituted or unsubstituted C 1-10 alkyl; R 5 is independently chosen from H or substituted or unsubstituted C 1-10 alkyl; R 6 is independently chosen from H or substituted or unsubstituted C 1-10 alkyl; and a in formula (1) is an integer from 0 to 2, and a in formula (2) is an integer from 0 to 3, and wherein the second monomer is of formula (3A):
wherein each R 7 is independently chosen from H, substituted or unsubstituted C 1-6 alkyl, substituted or unsubstituted C 6-20 aryl, or substituted or unsubstituted C 4-20 heteroaryl; R 8 is substituted or unsubstituted C 6-20 aryl, or substituted or unsubstituted C 4-20 heteroaryl; R 9 is independently chosen from substituted or unsubstituted C 1-6 alkyl, substituted or unsubstituted C 6-20 aryl, or substituted or unsubstituted C 4-20 heteroaryl; and Ar 1 is an aromatic moiety; and
(b) exposing the polymeric sensing layer to an atmosphere comprising a gas-phase analyte.
9. The method of claim 8 , wherein adsorption of the gas-phase analyte is effective to change a property of the gas sensor that results in a change in an output signal from the gas sensor.
10. The method of claim 9 , further comprising, in sequence:
(c) exposing the sensor to a second atmosphere effective to reduce the content of the gas-phase analyte in the sensor;
(d) allowing the resonant frequency of the acoustic wave sensor to recover to a baseline frequency; and
(e) exposing the sensor to a third atmosphere comprising a gas-phase analyte;
wherein the step (d), (e), and (f) sequence is performed one or more times.
11. The method of claim 8 , wherein the gas-phase analyte is an organic material.
12. The method of claim 11 , wherein the gas-phase analyte is chosen from one or more of benzene, toluene, xylene, mesitylene, ethanol, formaldehyde, acetaldehyde, acetone, acetic acid, or a trialkylamine.
13. The method of claim 8 , wherein the gas-phase analyte is an inorganic material.