# US 12,216,310 B2 · Mixed-matrix composite integrated fiber optic CO2 sensor

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- Number: US 12,216,310 B2
- Document ID: US12216310B2
- Status: Granted
- Kind: B2
- Application number: 17/883,553
- Filed: 2022-08-08
- Published: 2023-02-09
- Granted: 2025-02-04
- Earliest claimed: 2021-08-06
- Assignees: Battelle Memorial Institute
- Applicants: Battelle Memorial Institute
- Inventors: Ki-Joong Kim; Jeffrey T. Culp; James E. Ellis
- Web page: https://patentgrep.com/patent/US12216310B2

## CPC

- C03C 3/06: with more than 90% silica by weight, e.g. quartz {(C03C3/045 takes precedence)}
- G02B 6/02395: {Glass optical fibre with a protective coating, e.g. two layer polymer coating deposited directly on a silica cladding surface during fibre manufacture (G02B6/02052, G02B6/02057, G02B6/024, G02B6/032, G02B6/105, G02B6/14 take precedence; coating on fibre gratings G02B6/02104; multilayer core or cladding G02B6/036; reinforcing splice joints G02B6/2558; optical cables, i.e. comprising protective structures external to the protective coating such as a jacket or plural coated optical fibres G02B6/44; coating of glass to obtain optical fibres C03C25/104)}
- C03C 13/045: {Silica-containing oxide glass compositions}
- C03C 25/106: Single coatings
- C03C 25/40: Organo-silicon compounds
- C03C 25/42: Coatings containing inorganic materials
- C03C 25/47: containing particles, fibres or flakes, e.g. in a continuous phase
- C09D 7/61: inorganic
- C09D 183/04: Polysiloxanes
- G01N 21/59: Transmissivity (G01N21/25 takes precedence)
- G01N 21/7703: {using reagent-clad optical fibres or optical waveguides (using measurement of total internal reflection or attenuated total reflection G01N21/552; optical fibres or waveguides per se G02B)}
- B82Y 20/00: Nanooptics, e.g. quantum optics or photonic crystals
- B82Y 35/00: Methods or apparatus for measurement or analysis of nanostructures
- C03C 2213/00: Glass fibres or filaments
- C08G 77/04: Polysiloxanes
- C08K 2003/2231: {of tin}
- C08K 2003/343: {Peroxyhydrates, peroxyacids or salts thereof}
- G01N 2021/7709: {Distributed reagent, e.g. over length of guide}
- Y02C 20/40: of CO2
- C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- 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)
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]

## Abstract

A mixed-matrix composite integrated fiber-optic (FO) sensor system was developed that reliably operates as a detector for gas-phase and dissolved CO2. A mixed-matrix composite sensor coating on the FO sensor comprising plasmonic nanocrystals and zeolite embedded in a polymer matrix. The mixed-matrix composite FO sensor showed excellent reversibility/stability in a high humidity environment and sensitivity to gas-phase CO2 over a large concentration range. The sensor exhibited the ability to sense CO2 in the presence of other geologically relevant gases. A prototype FO sensor configuration which possesses a robust sensing capability for monitoring dissolved CO2 in natural water was demonstrated. Reproducibility was confirmed over many cycles, both in a laboratory setting and in the field.

## Claims

### Claim 1

An optical fiber comprising a coating composition disposed on the exterior of a glass fiber; and
wherein the coating composition comprises an optical response enhancer and sorbent particles disposed in a polymer, wherein the polymer is hydrophobic.

### Claim 2 (depends on 1)

The optical fiber of claim 1 wherein the glass fiber is at least 90 wt % silica, or at least 99 wt % silica.

### Claim 3 (depends on 1)

The optical fiber of claim 1 wherein the optical response enhancer is a plasmonic nanocrystal.

### Claim 4 (depends on 1)

The optical fiber of claim 1 wherein the optical response enhancer comprises ITO.

### Claim 5

The optical fiber of any of the above claims wherein the coating composition has a refractive index within the range of 1.30 to 1.70 or 1.30 to 1.60.

### Claim 6 (depends on 1)

The optical fiber of claim 1 wherein the optical response enhancer comprises plasmonic nanocrystals having at least one dimension in the size range of 1 nm to 30 nm or 2 nm to 20 nm, or 5 to 20 nm, or 20 to 200 nm based on the smallest diameter of particles of the plasmonic nanocrystals.

### Claim 7 (depends on 1)

The optical fiber of claim 1 wherein the length of the coating composition is 5 to 10 cm.

### Claim 8 (depends on 1)

The optical fiber of claim 1 wherein the sorbent particles comprise a zeolite.

### Claim 9 (depends on 1)

The optical fiber of claim 1 wherein the optical response enhancer comprises plasmonic nanocrystals and wherein the sorbent mass average particle size of the sorbent is larger than the mass average particle size of the plasmonic nanocrystals.

### Claim 10 (depends on 1)

The optical fiber of claim 1 wherein the polymer comprises a polysiloxane.

### Claim 11 (depends on 1)

The optical fiber of claim 1 wherein the coating composition comprises 0.5-20 wt % plasmonic nanocrystals; at least 5 wt % sorbent, or 5 to 80 wt % sorbent; and at least 10 wt % polymer wherein the polymer absorbs less than 5 wt % of water at 97% humidity at 20° C.

### Claim 12 (depends on 1)

The optical fiber of claim 1 wherein the optical response enhancer comprises plasmonic nanocrystals and wherein at least 50 mass % or at least 80 mass % of the nanocrystals have sizes in the range of 5 to 40 nm, or 5 to 25 nm, or 6 to 20 nm.

### Claim 13

An optical fiber comprising a coating composition disposed on the exterior of a glass fiber; and
wherein the coating composition comprises an optical response enhancer, wherein the optical response enhancer is a light absorbing material that, when present in the polymer exhibits at least two times greater absorption or in the range of 2 to ten times greater absorption of the light reflected from the coating composition at the measurement wavelength as compared to the absorption from the coating composition without the optical response enhancer and as compared to the coating composition in an absence of CO2 and CH4.

### Claim 14

A coating composition comprising: plasmonic nanocrystals and sorbent particles disposed in a polymer; wherein the polymer is hydrophobic.

### Claim 15 (depends on 14)

The coating composition of claim 14 wherein the sorbent particles comprise a zeolite.

### Claim 16 (depends on 14)

The coating composition of claim 14 further comprising an optical response enhancer; wherein the optical response enhancer is a light absorbing material that, when present in the polymer which coats an optical fiber to a thickness of 5 μm, exhibits at least two times greater absorption or in the range of 2 to ten times greater absorption of the light absorbed from the coating composition at the measurement wavelength as compared to the absorption from the coating composition without the optical response enhancer and as compared to the coating composition in an absence of CO2 and CH4.

### Claim 17 (depends on 14)

A sensor, comprising: a glass fiber coated with the coating composition of claim 14.

### Claim 18 (depends on 17)

The sensor of claim 17 wherein the glass fiber is disposed in a metal or plastic tube having a plurality of holes formed along the length of the tube.

### Claim 19

A method of making a composite, comprising: mixing a suspension of polymer, optical enhancer and sorbent particles, wherein the polymer is hydrophobic; applying the suspension to a substrate, and curing or setting the polymer.

### Claim 20 (depends on 19)

The method of claim 19 wherein the optical enhancer comprises plasmonic nanocrystals, and wherein the substrate is a glass fiber.

### Claim 21

A method of measuring an amount of CO2, H2, or CH4, comprising:
exposing a sensor, which comprises a coating composition disposed on the exterior of a glass fiber; wherein the coating composition comprises an optical response enhancer and sorbent particles disposed in a polymer, to the CO2, H2, or CH4, and measuring light transmission through the glass fiber.