CO2 Sensor Using Carbon Nanotube-Polymer Composite Films
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current CO2 sensors for HVAC and industrial applications lack long-term reliability and are costly and power-intensive, making them unsuitable for low-cost, low-power monitoring solutions.
Innovation Solution
A composite film comprising a carbon nanotube film with a CO2 absorbing layer made of a mixture of branched polyethylenimine, polyethylene glycol, and poly[1-(4-vinylbenzyl)-3-methylimidazolium tetrafluoroborate] is used for chemiresistive sensing, leveraging the affinity of ionic liquids for CO2 and the conductivity of carbon nanotubes to detect CO2 concentrations effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If NDIR sensors are used for CO2 detection, then measurement precision is improved, but use of energy increases and reliability deteriorates
Solution Approach 1:
The patent changes the sensing mechanism from optical (NDIR) to electrical (chemiresistive), fundamentally altering the operating parameters. The chemiresistive sensor uses electrical resistance changes in response to CO2-induced doping of carbon nanotubes, enabling operation at ultra-low power levels while maintaining sufficient precision for occupancy monitoring applications
Solution Approach 2:
The patent employs composite materials including carbon nanotubes functionalized with polyethylenimine and ionic liquid coatings. This composite structure enhances the sensor's CO2 sensitivity and selectivity, allowing for reliable detection at low power consumption by maximizing the electrical response to CO2 exposure
2Measurement precision
If NDIR sensors are used for CO2 detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts only the essential sensing function from complex NDIR systems by using a simple chemiresistive mechanism. The sensor consists of a carbon nanotube film deposited on electrodes, eliminating the need for infrared light sources, optical filters, and complex signal processing circuits required by NDIR sensors
Solution Approach 2:
The patent employs inexpensive, easily fabricatable materials such as carbon nanotube films and polymer coatings that can be deposited using simple techniques. This approach prioritizes cost-effectiveness and ease of manufacturing over the long-term durability of expensive NDIR components, suitable for disposable or frequently replaced sensor applications
3Use of energy by moving object
If chemiresistive sensing with carbon nanotubes is used, then use of energy is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent applies local quality enhancement by functionalizing specific regions of the carbon nanotube film with polyethylenimine and ionic liquid coatings. These functional groups are strategically placed to maximize CO2 interaction and electrical response, concentrating the sensing activity in high-sensitivity zones while maintaining overall low power consumption
Solution Approach 2:
The patent utilizes the porous and high-surface-area structure of carbon nanotube films to enhance CO2 adsorption capacity. The nanotube network provides extensive surface area for CO2 molecules to interact with functional groups, amplifying the electrical response signal and improving detection precision even at low power operation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composite film enables sensitive CO2 detection in ppm ranges relevant for indoor occupancy monitoring with lower power consumption and cost compared to traditional sensors, demonstrating a promising alternative for low-cost and low-power CO2 sensing.
Implementation Method 1
the composite film enables sensitive CO2 detection in ppm ranges relevant for indoor occupancy monitoring
Implementation Method 2
leveraging the affinity of ionic liquids for CO2 and the conductivity of carbon nanotubes to detect CO2 concentrations effectively
Implementation Method 3
a CO2 absorbing layer deposited on the carbon nanotube film, wherein the CO2 absorbing layer comprises a mixture of a branched polyethylenimine, a polyethylene glycol, and poly[1-(4-vinylbenzyl)-3-methylimidazolium tetrafluoroborate]
Implementation Method 4
leveraging the affinity of ionic liquids for CO2
Data Source
AI summary
The present disclosure relates to a novel composite film configured for CO2 sensing, and the method of making and using the novel composite film. The novel composite film comprises a carbon nanotube film and a CO2 absorbing layer deposited on the carbon nanotube film, wherein the CO2 absorbing layer comprises a mixture of a branched polyethylenimine, a polyethylene glycol, and poly[1-(4-vinylbenzyl)-3-methylimidazolium tetrafluoroborate] of formula I:wherein n ranges from 10-300.