Researchers Use Polymer Composite Coating in Optical Fiber Sensors to Detect GHG

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NETL and University of Pittsburgh research team demonstrates the use of plasmonic nanomaterials (pNPs) and porous polymer composite coating in optical fiber sensing technologies that can detect energy-relevant gases, such as carbon dioxide (CO₂) and methane (CH₄).

The technology can help ensure safer, quicker and more secure underground storage and pipeline monitoring.

pNPs to Enhance Monitoring of Optical Fiber Sensors

Optical fiber sensors offer advantages over other types of sensors because they are small, lightweight, can endure high temperatures and pressures and are immune to electromagnetic interference. In addition, the optical fiber sensors feature long-reach and spatially distributed monitoring.

The latest research demonstrates how plasmonic nanoparticles (pNPs) can be incorporated into the porous polymer coating to enhance the monitoring capabilities of optical fiber sensors to build on extensive distributed sensor technology research at NETL.

pNPs, including gold, silver and platinum particles, are discrete metallic particles or metal oxide particles such as tin-doped indium oxide (ITO) that have unique optical properties due to their size and shape and are increasingly being incorporated into commercial products and technologies.

pNPs have unique optical, electrical and thermal properties that make them effective for use in applications such as antimicrobial coatings and molecular diagnostics.

Composite Film Used as Signal Transducer for Sensing Gas

Sensing technologies based on pNPs are of interest for various chemical, biological, environmental and medical applications. Plasmonic gas sensors exhibit high sensitivity, but until recently have not been demonstrated to chemically stable gases such as CO₂ at room temperature.

In this specific case, NETL researchers Ki-Joong Kim, Jeffrey T. Culp, Jeffrey Wuenschell, Ali K. Sekizkardes and former NETL researchers Roman A. Shugayev,and Paul R. Ohodnicki developed the highly sensitive material that can be used to detect CO₂ (or CH₄) in ambient environments.

The researchers created a composite film that provides distinct and tunable optical features on a fiber optic platform that can be used as a signal transducer for gas sensing under atmospheric conditions.

Tuning Plasmon Resonance

Researchers explain that by varying the pNPs content in a polymer matrix, the optical behavior of the composite film can be tuned to affect the operational wavelength by over several hundred nanometers and the sensitivity of the sensor in the near-infrared range.

Tuning plasmon resonance across the near-infrared range is particularly important in distributed or quasi-distributed sensing approaches, which are more compatible with distributed interrogation systems.

The research also demonstrated that the pNPs-polymer composite film exhibits remarkable long-term stability by mitigating the physical aging issue of the polymer. The sensor can operate atmospheric conditions without significant signs of degradation.

“Developments of sensing technologies are important to a clean energy future, including safe underground storage of CO₂ and detection of CH₄ leaks,” said Ruishu Wright, functional materials team, NETL.

Real-time Monitoring

“Visibility and monitoring are important for evaluating and managing operational risks of underground CO₂ storage. Real-time monitoring is needed to assure storage and pipeline infrastructure integrity and to detect early signs of gas leakage,” continued Wright.

There are many commercial gas sensors for CO₂ or CH₄ in operation, including catalytic combustion sensors, electrochemical sensors, thermo-conductivity sensors, resistive sensors, acoustic leak sensors and optical-based sensors. But the challenge is that existing sensor technologies are mostly point or standoff sensors.

“There is a real need for wide-area and long-distance monitoring for CO₂ and CH₄ leak detection in large-scale storage facilities and for CH4 gas detection at well sites and industrial facilities. Early leak detection of greenhouse gases will help to mitigate gas emissions and combat global warming,” added Wright.

Source: NETL