Metal Oxide Polymer Composite pH Sensor for Miniaturization
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Solution Overview
Problem
Conventional pH sensors, including glass and metal oxide-based sensors, face issues such as high impedance, mechanical fragility, instability in acidic solutions and high temperatures, slow response, and interference from halogen anions and redox active species, making them unsuitable for miniaturization and certain industrial applications.
Innovation Solution
A pH sensor comprising a metal oxide-polymer composite with Ta2O5 and RuO2 in a specific weight ratio, dispersed in a polymer matrix with carbon-based conductors, which provides improved sensitivity, resistance to interfering ions, and robustness, allowing for miniature designs and use in diverse environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass pH electrodes are used, then sensitivity and stability are improved, but mechanical fragility and vulnerability to membrane fouling increase
Solution Approach 1:
The patent applies composite materials by combining metal oxide particles (Ta2O5 and RuO2) with polymer matrix materials to create a composite pH sensor electrode. This composite structure provides both the sensing capability of metal oxides and the mechanical robustness of polymers, resolving the contradiction between sensitivity/stability and mechanical strength.
2Measurement precision
If glass pH electrodes are used, then measurement accuracy is improved, but suitability for miniaturization deteriorates
Solution Approach 1:
The patent changes the material parameters from traditional glass to metal oxide-polymer composites, enabling the electrode to be manufactured in miniaturized forms while maintaining pH measurement accuracy. The composite material allows for smaller electrode dimensions without sacrificing sensing performance.
3Strength
If metal oxide films are used for pH sensing, then robustness is improved, but interference from halogen anions and redox active species increases
Solution Approach 1:
The patent merges multiple metal oxide materials (Ta2O5 and RuO2) in specific weight ratios within a polymer composite. This combination leverages the complementary properties of each metal oxide to maintain robustness while reducing interference from halogen anions and redox active species through synergistic effects.
Solution Approach 2:
The patent optimizes the weight ratio parameters of Ta2O5 to RuO2 (specifically 70:30 to 30:70) to achieve the optimal balance between robustness and resistance to interference from harmful species, demonstrating parameter optimization to resolve the technical contradiction.
4Measurement precision
If conventional metal oxide electrodes are used, then pH sensing capability is achieved, but hysteresis and drift occur during repeated use
Solution Approach 1:
The patent uses composite materials combining metal oxides with polymer matrices to create a more stable electrode structure that maintains pH sensing capability while significantly reducing hysteresis and drift during repeated use. The polymer matrix provides structural stability that prevents the hysteresis and drift issues observed in conventional metal oxide electrodes.
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 pH sensor offers fast response times, reduced interference, and economic fabrication, enabling its use in industrial, environmental, and biological applications, with improved sensitivity and stability across a wide pH range, and resistance to high temperatures and pressures.
Implementation Method 1
Electrode potentials due to the oxidation-reduction reaction of the metal oxides are dependent on the hydrogen ion concentration
Implementation Method 2
carbon-based conducting particles dispersed in a polymer matrix
Data Source
Figure 1~2
Figure 3a~3b
Figure 4~5
AI summary
A pH sensor comprising a metal oxide-polymer composite, comprising: a continuous polymer resin matrix; and a solid particulate component dispersed in the polymer resin matrix comprising (i) metal oxides and (ii) a particulate carbon-based conductor wherein the metal oxides comprise Ta2O5 and RuO2 in a weight ratio of Ta2O5 : RuO2 (on the basis of weight of metal component) in the range of from 90:10 to 10:90.