Switchable single-walled carbon nanotube-polymer composites for CO2 sensing
Inventors
Swager, Timothy • Yoon, Bora • Walsh, Gary
Assignees
Massachusetts Institute of Technology • United States Department of the Army
Publication Number
US-11733192-B2
Publication Date
2023-08-22
Expiration Date
2039-09-17
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Abstract
A sensor for carbon dioxide can include an amidine functional group.
Core Innovation
The invention features a composition and sensor for detecting carbon dioxide using a polymer with amino and alkylazide side chains associated with a conductive material. The polymer can be amidine-functional and derived from alkylazido groups, associated particularly with carbon conductive materials such as single-walled carbon nanotubes (SWCNTs). The sensor includes an amidine-functional polymer associated with a carbon conductive material immobilized on a substrate surface, enabling the detection of CO2 by measuring conductivity changes.
The problem being solved addresses the growing industrial need for precise monitoring of CO2 levels, especially in agriculture and food packaging. Existing challenges include detecting optimal CO2 concentrations critical for plant photosynthesis, preventing plant damage from excess CO2, and monitoring microbial activity in food packaging to ensure quality and shelf life. The invention provides a sensitive, selective, and reversible chemiresistive sensor responsive to CO2 in humid environments, overcoming limitations in current detection methods.
Claims Coverage
The patent includes multiple independent claims covering compositions, sensors, methods of detection, and preparation involving a polymer with amino and alkylazide side chains associated with conductive materials, focusing on CO2 detection.
Composition comprising a polymer with pyridyl amino and alkylazide side chains associated with conductive material
Discloses a composition comprising a polymer including a pyridyl amino side chain and an alkylazide side chain, associated with a conductive material such as carbon nanotubes, conductive polymers, or metal oxides.
Sensor for detecting carbon dioxide with amidine-functional polymer on substrate
Describes a sensor comprising a substrate and a composition of the specified polymer and conductive material on the substrate, where the polymer is an amidine-functional polymer immobilized on the substrate surface, and the conductive material includes carbon nanotubes.
Method of detecting carbon dioxide by measuring conductivity change
Covers a method involving exposing the specified composition to a sample and measuring the conductivity change to detect carbon dioxide, with the polymer optionally immobilized on a substrate surface.
Method of preparing a sensor by linking polymer composition to substrate, quaternizing and functionalizing side chains
Involves preparing a sensor by linking the polymer composition with amino and alkylazide side chains to a substrate, quaternizing the amino side chain, and functionalizing the alkylazide side chain by introducing an amidine-functional group.
The claims cover the innovative composition of a polymer with specific side chains associated with conductive materials, a sensor using that composition immobilized on a substrate for CO2 detection, and methods for detecting CO2 and preparing such sensors by specific chemical functionalization processes.
Stated Advantages
The sensor exhibits reversible and substantial conductance changes upon exposure to CO2 under humid conditions.
High selectivity for CO2 detection over other atmospheric gases such as oxygen and argon is demonstrated.
The sensor is stable with a robust surface-anchored polymer-SWCNT composite allowing reliable CO2 detection.
Documented Applications
Monitoring and detecting carbon dioxide levels in greenhouse crop production to optimize photosynthesis and improve crop productivity.
Detecting CO2 generated by microbial metabolic activity as an indicator of food spoilage in modified atmosphere packaging to ensure food quality and predict shelf life.
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