Polyimide Ammonia Sensor with Reversible Conductivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sensors fail to reliably detect ammonia gas and/or vapors, especially at low-molarity concentrations, and require complex processes, expensive materials, or specific substrates.
Innovation Solution
A sensor utilizing a polyimide-based polymeric layer deposited on various substrates, which changes electric resistance in response to ammonia presence, allowing for reliable detection at room temperature without additives or nanoparticles, and is biocompatible with excellent thermal and chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sensors (electrically conductive polymers, metal oxides, carbon structures) are used for ammonia detection, then detection capability is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent uses polyimide, a commercially available and inexpensive polymer, instead of expensive specialized materials like conductive polymers, metal oxides, or carbon nanotubes. The sensor can be manufactured using simple deposition processes without requiring complex nanofabrication techniques, making it cost-effective and easier to produce at scale
Solution Approach 2:
The patent changes the operating temperature parameter from elevated temperatures (required by many conventional ammonia sensors) to room temperature operation. This is achieved by utilizing the specific interaction between polyimide and ammonia that produces detectable electrical signals at ambient conditions, simplifying the sensor design and reducing energy requirements
2Reliability
If conventional sensors are used for ammonia detection, then detection is possible, but energy consumption increases due to heating requirements
Solution Approach 1:
The polyimide material inherently interacts with ammonia gas to produce measurable electrical signals without requiring external heating or energy input. The sensor utilizes the natural affinity between polyimide and ammonia, eliminating the need for energy-intensive heating elements that are common in conventional ammonia detection systems
3Manufacturing precision
If complex manufacturing processes are used, then sensor performance is improved, but production cost and time increase
Solution Approach 1:
The patent uses polyimide that has already been synthesized and is commercially available, eliminating the need for complex in-situ polymerization or material synthesis steps during sensor manufacturing. The material is deposited in its ready-to-use form, significantly simplifying the manufacturing process and increasing production efficiency
Solution Approach 2:
The patent utilizes the inherent electrical properties of polyimide that change in response to ammonia exposure. The polyimide layer exhibits measurable electrical signal changes when exposed to ammonia gas, providing a direct and simple detection mechanism without requiring additional functional layers or complex transduction mechanisms
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 sensor effectively detects ammonia at low concentrations, operates at room temperature, and is energy-efficient, with the polyimide layer exhibiting reversible conductivity changes, enabling reliable ammonia detection in aqueous solutions and varying environments.
Implementation Method 1
a polymeric layer (14) having electrically conductive properties when that region adsorbs a quantity of ammonia
Implementation Method 2
the polyimide layer exhibiting reversible conductivity changes, enabling reliable ammonia detection
Data Source
Figure 1~2
Figure 3
AI summary
The sensor (10) comprises a substrate (12) and a polymeric layer (14) deposited on the substrate (12). The polymeric layer (14) includes polyimide having electrically conductive properties when said polymeric layer (14) adsorbs a quantity of ammonia. The polyimide has imide groups capable of reacting with the adsorbed quantity of ammonia to turn into amide groups. Thus, the electric resistance of the polyimide is variable according to the quantity of ammonia gas or vapour adsorbed by the polymeric layer (14). The sensor (10) comprises a pair of electrodes (16) electrically connected to the polymeric region (14) and configured for allowing the detection of the electric resistance value of the polyimide.