Mixed-matrix composite integrated fiber optic CO2 sensor

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.

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.

A coating composition comprising:

• plasmonic nanocrystals and sorbent particles disposed in a polymer;
• wherein the polymer is hydrophobic.

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.

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.