Polysulfone-Coated Carbon Electrodes for Accurate Low-Buffer pH Sensing
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Solution Overview
Problem
Existing electrochemical pH sensors face inaccuracies in low buffering capacity solutions due to carbon material perturbing the pH proximal to the working electrode, and there is a need for accurate pH measurement in environments like seawater and low electrolyte media.
Innovation Solution
A composite working electrode with a redox active species configured for hydrogen bonding through a carbon ring, using a polysulfone-coated carbon material to stabilize the electrode surface and promote proton transfer, and a set of active redox species that form hydrogen bonds through a five or six-membered ring with a substituted oxygen family atom, allowing accurate pH measurement in low buffering capacity solutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon material is used in the working electrode, then electrochemical activity is improved, but pH measurement accuracy deteriorates due to carbon material perturbing the pH proximal to the working electrode
Solution Approach 1:
A polymer coating layer is introduced as an intermediary between the carbon material and the aqueous solution. This coating acts as a barrier that prevents direct interaction between the carbon material and the solution, thereby eliminating the pH perturbation effect while still allowing proton transfer for pH sensing. The polymer layer serves as a mediator that decouples the electrochemical activity from the harmful pH disturbance.
Solution Approach 2:
The patent modifies the surface properties of the carbon material by changing its chemical state through polymer coating. This parameter change transforms the carbon material from a directly exposed state (which perturbs pH) to a coated state (which maintains electrochemical activity without pH perturbation). The coating changes the interfacial properties between the electrode and solution.
2Measurement precision
If glass electrode is used for pH measurement, then measurement accuracy is improved, but device fragility and operational complexity worsen due to regular calibration requirements and storage conditions
Solution Approach 1:
The patent replaces the mechanical glass electrode system with an electrochemical sensor based on redox-active species. This substitution eliminates the need for mechanical glass components that are fragile and require careful handling. The electrochemical system uses molecular self-assembly and redox reactions instead of mechanical glass structures, thereby reducing fragility and operational complexity.
Solution Approach 2:
The electrochemical sensor utilizes self-assembly mechanisms where the redox-active species automatically organize on the electrode surface without requiring manual assembly or calibration. The system performs its own function through inherent electrochemical reactions, eliminating the need for external calibration procedures and specialized storage conditions that glass electrodes require.
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 stable, reproducible, and defined redox output in low buffering capacity solutions, improving accuracy and stability of pH measurement in environments such as water and seawater.
Implementation Method 1
an electrochemical sensor comprising said composite working electrode for electrochemical pH sensing using a chemistry/redox active species configured to provide for hydrogen bonding
Implementation Method 2
a hydrogen atom attached to a carbon ring is configured so as to provide for hydrogen bonding with the bound oxygen family atom
Data Source
Figure 1(A)~1(A-1)
Figure 1(B)~2
Figure 3
AI summary
A composite working electrode comprising at least one polysulfone coated carbon material and at least one active redox species comprising an oxygen family atom bound in a ring structure, wherein the ring structure is substituted with a carbon ring, and wherein a moiety containing a hydrogen atom is attached to the carbon ring such that it is configured to provide for hydrogen bonding with the bound oxygen family atom and an electrochemical sensor comprising said composite working electrode.