Polymer Membrane pH Transducer for Miniaturization
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Solution Overview
Problem
Existing pH measurement technologies, such as glass electrodes and ISFETs, face challenges including mechanical fragility, sensitivity to handling, limited miniaturization, and instability due to high impedance, as well as chemical sensitivity and inability to be sterilized, while optical pH measurements are prone to cross-sensitivities from other ions.
Innovation Solution
A potentiometric measuring transducer using a selectively conducting polymer membrane that enhances mechanical and chemical stability, allowing for higher ion conductivity and miniaturization, with a polymer membrane that preferentially conducts H+ or OH- ions, reducing interference from other ions and improving selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a glass membrane is used in a potentiometric measuring transducer, then precise and reliable pH measurement results are achieved, but the transducer becomes mechanically fragile and sensitive to handling
Solution Approach 1:
The patent changes the material parameter of the membrane from traditional pH-sensitive glass to a polymer membrane with selective ion conductivity. This parameter change maintains the ability to generate pH-dependent potential while dramatically improving mechanical strength and handling robustness.
Solution Approach 2:
The patent employs a composite structure combining a polymer membrane with selective H+/OH- ion conductivity. This composite material approach integrates the ion-selective functionality with mechanically robust polymer material, eliminating the fragility of glass membranes.
2Volume of moving object
If the glass membrane area is reduced for miniaturization, then the transducer size is reduced, but the resistance of the measuring half cell increases
Solution Approach 1:
The patent changes the conductivity parameter of the membrane material from glass to polymer, which has inherently higher ion conductivity. This allows miniaturization without increasing resistance, as the polymer membrane maintains low resistance even at reduced areas.
Solution Approach 2:
The patent substitutes the glass membrane-based potentiometric system with a polymer membrane-based system that has superior electrical properties. The polymer membrane's higher ion conductivity enables miniaturization while maintaining measuring stability.
3Strength
If optical pH measurement is used, then mechanical robustness is improved, but cross-sensitivity to other ions occurs
Solution Approach 1:
The patent applies local quality by making the polymer membrane selectively conductive to H+ and/or OH- ions. This selective ion conductivity at the membrane level ensures that only the target ions contribute to the measurement signal, eliminating cross-sensitivity to other ions while maintaining mechanical robustness.
Solution Approach 2:
The polymer membrane acts as an intermediary that selectively transports H+ and/or OH- ions while blocking other ions. This mediator approach ensures measurement selectivity without requiring optical methods, combining the advantages of robustness with ion-selective measurement.
4Volume of moving object
If a polymer membrane with high ion conductivity is used, then miniaturization is enabled, but manufacturing complexity increases
Solution Approach 1:
The patent changes the material parameters of the membrane to achieve optimal balance between ion conductivity and manufacturability. The polymer membrane is designed with specific conductivity characteristics that enable miniaturization while remaining compatible with standard manufacturing processes.
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 solution provides a more robust, stable, and selective pH measurement system with reduced risk of mechanical damage and chemical interference, enabling improved measurement accuracy and miniaturization, while maintaining high selectivity and stability.
Implementation Method 1
at least one polymer membrane (10) selectively conducting H+ and/or OH− ions
Implementation Method 2
a polymer membrane selectively conducting H+ ions or protons is a polymer membrane, whose conductivity or permeability to protons is higher than its conductivity or permeability to other ions present in the measured medium
Implementation Method 3
The most popular technology for determining the pH value of a measured solution is potentiometric measurement
Implementation Method 4
a potential sensing element, for example, a chloridized silver wire, extends into the buffer solution. In contact with the measured medium, a measuring half cell potential dependent on the pH value forms at the glass membrane
Data Source
AI summary
A measuring transducer, which is embodied to produce and output a measurement signal dependent on the content of H+ and/or OH− ions present in a measured medium, wherein the measuring transducer has, in a region provided for contact with the measured medium, at least one polymer membrane selectively conducting H+ and/or OH− ions. The polymer membrane can comprise an H+ ion conducting polymer and/or an OH− ion conducting polymer.