Annealed metal nano-particle decorated nanotubes
Inventors
Iftime, Gabriel • Kim, Beomseok • Smith, Clinton • Cocker, Eric • Wei, Junhua • SCHWARTZ, DAVID ERIC • Meyyappan, Meyya • Pandey, Rahul • Zhang, Yong
Assignees
Bay Systems Consulting Inc • National Aeronautics and Space Administration NASA • Xerox Corp
Publication Number
US-11072531-B2
Publication Date
2021-07-27
Expiration Date
2037-12-22
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Abstract
Disclosed are methods and systems of providing carbon nanotubes decorated with polymer coated metal nanoparticles. Then, annealing the metal coated carbon nanotubes to reduce a quantity of hydrophilic components of the polymer coating.
Core Innovation
The invention relates to metal nanoparticle-decorated carbon nanotubes, specifically carbon nanotubes decorated with polymer coated metal nanoparticles, and methods of producing these materials by annealing to reduce hydrophilic components of the polymer coating. This annealing step carbonizes the polymer coating and removes oxygen-containing functional groups from both the polymer and carbon nanotubes, enhancing properties of the nanoparticle-carbon nanotube composite.
The problem being solved is the limitation of existing natural gas and methane gas sensors, which may have limited detection capability, reduced lifespan, or decreased reliability due to the presence of water vapor in ambient conditions. Humidity saturates sensors, reducing their effectiveness. Existing sensor technologies have trade-offs in size, power consumption, sensitivity, and expense, and some compact sensors are adversely affected by water vapor due to hydrophilic interactions.
The invention aims to provide a gas sensor using carbon nanotube materials decorated with metal nanoparticles where the metal nanoparticles are coated with polymers to attach them and reduce water vapor adsorption. Then, an annealing process is applied to decrease hydrophilic components and improve hydrophobic characteristics, which enhances sensor sensitivity, reduces water interference, and improves operational lifespan under varied humidity environments. The resulting material changes resistivity upon gas adsorption, allowing measurement of gas concentration.
Claims Coverage
The patent contains one independent method claim defining a process for creating annealed metal nanoparticle decorated carbon nanotubes with reduced hydrophilicity.
Decorator method for carbon nanotubes with polymer coated metal nanoparticles
Mixing a dispersion of carbon nanotubes with a dispersion of polymer coated metal nanoparticles, where the polymer coating both attaches metal nanoparticles to the carbon nanotubes and reduces adsorption of water vapor by the nanoparticles.
Annealing to reduce hydrophilic components
Performing annealing on the decorated carbon nanotubes to decrease the quantity of hydrophilic components of the polymer coating, thereby modifying the interface and properties of the coated nanoparticles.
The claims cover a method comprising decorating carbon nanotubes with polymer coated metal nanoparticles to reduce water vapor adsorption, followed by annealing to remove hydrophilic polymer components, producing hydrophobic composite materials for gas sensing.
Stated Advantages
Enhanced sensitivity resulting from lower polymer content and more direct contact between metal nanoparticles and carbon nanotubes after annealing.
Reduced water sensitivity due to removal of hydrophilic carboxyl and oxygen-containing functional groups leading to improved hydrophobicity.
Improved sensor performance in humid conditions, extending operating lifespan and reliability.
Smaller and low power sensors with improved detection capabilities for natural gas or methane.
Documented Applications
Use in methane and natural gas leak detection sensors capable of detecting hydrocarbon gases such as methane, ethane, and propane.
Gas sensors employing metal nanoparticle decorated single-walled carbon nanotubes applied onto interdigitated electrodes to measure resistivity changes caused by gas adsorption.
Printed sensors with nanoparticle/nanotube ink deposited on substrates with various electrode materials for monitoring natural gas in industrial or ambient environments.
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