Single-Layer pH-Sensitive Electrode with Composite Materials
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Solution Overview
Problem
Existing pH sensors, particularly glass pH electrodes, face challenges such as high impedance, mechanical fragility, instability in extreme conditions, slow response, and difficulties in miniaturization, making them unsuitable for certain applications, while all-solid pH sensors require complex multi-step processes and conditioning steps that affect sensitivity and stability.
Innovation Solution
A pH-sensitive electrode is developed with a single layer combining electrochemical transducers and pH-sensitive elements, such as transition metal oxides and redox molecules, allowing for a rapid and easy-to-implement process that maintains sensitivity and stability, enabling miniaturization and broad pH range linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single layer combining electrochemical transducer and pH-sensitive elements is used, then device complexity and manufacturing difficulty are reduced, but maintaining sensitivity and stability comparable to traditional two-layer configurations becomes challenging
Solution Approach 1:
The patent merges the electrochemical transducer and pH-sensitive elements into a single integrated layer, eliminating the need for separate transduction layer and pH layer depositions. This combination reduces device complexity and manufacturing steps while maintaining the functional performance through the synergistic interaction of components within the same layer matrix.
Solution Approach 2:
The electrode utilizes a composite material system comprising conductive polymers (such as polyaniline or polypyrrole), transition metal oxides (such as iridium oxide or ruthenium oxide), and carbon materials. This composite structure within the single layer provides both the electrochemical transduction capability and pH sensitivity simultaneously, resolving the contradiction between simplified structure and maintained performance.
2Ease of manufacture
If all-solid pH sensors are used to avoid glass electrode disadvantages, then robustness and miniaturization capability are improved, but the requirement for complex multi-step preparation processes and conditioning steps increases
Solution Approach 1:
The patent combines multiple functional components (electrochemical transducer and pH-sensitive elements) into a single layer that can be deposited in one step, eliminating the need for sequential deposition of transduction layer and pH layer. This single-step approach significantly simplifies the manufacturing process while maintaining the robustness and miniaturization advantages of all-solid pH sensors.
Solution Approach 2:
The integrated single-layer structure eliminates the need for separate conditioning steps that are typically required for traditional multi-layer electrodes. The synergistic interaction of components within the single layer enables the electrode to achieve optimal performance directly after deposition, reducing or eliminating the need for additional activation or conditioning procedures.
3Reliability
If traditional glass pH electrodes are used, then sensitivity and stability are maintained, but mechanical fragility and difficulty in miniaturization occur
Solution Approach 1:
The patent employs flexible, depositable materials such as conductive polymers and metal oxide nanoparticles that can be applied as thin films on various substrates. These materials replace the fragile glass membrane, creating a mechanically robust electrode structure that is resistant to breakage and suitable for miniaturization, while maintaining pH sensing functionality through the electrochemical reactions of the metal oxide components.
Solution Approach 2:
The electrode utilizes thin film structures of conductive polymers and metal oxide layers that can be deposited on flexible or rigid substrates. This thin film approach replaces the thick, rigid glass electrode structure, providing mechanical flexibility and robustness while enabling miniaturization. The thin film structure maintains sensitivity through the high surface area to volume ratio of the metal oxide particles.
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 pH-sensitive electrodes with sensitivity comparable to traditional two-layer configurations, offering improved stability, ease of preparation, and miniaturization capabilities, with linearity across a wide pH range (3-9) and reduced hysteresis, enhancing their applicability in various environments.
Implementation Method 1
The potential of the pH-sensitive electrode has, in fact, a linear relationship with the pH of the solution studied according to the Nernst equation
Implementation Method 2
a transduction layer 6 arranged on the conductive layer 5, this layer allows to convert an activity of a species in solution into an electric potential
Implementation Method 3
a pH-sensitive layer 7 arranged on the transduction layer 6, this layer is the sensitive part of the sensor since it is sensitive to the concentration of protons
Data Source
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Figure 5
AI summary
The present invention relates to a pH-sensitive electrode (10) comprising: (i) a conductive layer (12) disposed on an insulating support (11) and (ii) a pH-sensitive layer (13) disposed on the conductive layer (12), said pH-sensitive layer comprising an electrochemical transducer and pH-sensitive elements distributed within this pH-sensitive layer, said pH-sensitive elements being selected from the group consisting of transition metal oxides and pH-sensitive redox molecules. The present invention also relates to an all-solid-state pH sensor comprising such an electrode and their uses for measuring pH in a liquid medium.