Ion-Selective Electrode Casing Material for Stable Membrane Adhesion
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Solution Overview
Problem
Existing ion-selective electrodes using vinyl chloride resin casings suffer from plasticizer transfer to the casing, leading to changes in electrode performance over time, necessitating a trade-off between plasticizer transfer and membrane adhesion, which limits the storage life to about one year.
Innovation Solution
Using a methyl methacrylate acrylonitrile butadiene styrene (MABS) resin for the casing material, which minimizes plasticizer transfer and maintains adhesion with the sensitive membrane, ensuring long-term stability and efficient production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If vinyl chloride resin is used as casing material, then adhesion between sensitive membrane and casing is improved, but plasticizer transfer to casing increases
Solution Approach 1:
The patent changes the chemical composition parameters of the casing material from conventional vinyl chloride resin to a specific resin composition containing polyacrylonitrile (30-70 wt%), polymethyl methacrylate (10-40 wt%), and polyacrylic acid (5-20 wt%). This parameter change in material composition reduces the affinity between the casing and plasticizer while maintaining adequate adhesion to the sensitive membrane through the flow path structure.
Solution Approach 2:
The patent employs a composite resin material system combining polyacrylonitrile, polymethyl methacrylate, and polyacrylic acid in specific proportions. This composite material achieves a balance between reducing plasticizer transfer and maintaining structural integrity and membrane adhesion, resolving the contradiction between strong adhesion and low plasticizer transfer.
2Ease of manufacture
If vinyl chloride resin is used as casing material, then ease of manufacture is improved, but electrode performance stability deteriorates
Solution Approach 1:
The patent changes the material composition parameters to a three-component resin system with specific weight percentages. This composition provides both manufacturability through conventional molding processes and improved electrode performance stability by minimizing plasticizer transfer that causes performance degradation over time.
Solution Approach 2:
The patent provides a flow path within the casing that allows the sensitive membrane to contact the test solution while the bulk casing material maintains structural properties. The local structure at the membrane-casing interface is optimized for adhesion, while the bulk material composition is optimized for low plasticizer affinity, achieving both manufacturability and stability.
3Ease of manufacture
If vinyl chloride resin is used as casing material, then production cost is reduced, but storage life is limited
Solution Approach 1:
The patent modifies the resin composition parameters to use polyacrylonitrile-based composite materials that can be manufactured at reasonable costs through conventional processes. The improved chemical composition significantly extends storage life by preventing plasticizer transfer, achieving both cost-effectiveness and extended electrode lifespan exceeding one year.
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 MABS resin achieves both improved stability and adhesion, extending the ion-selective electrode's storage life and reducing maintenance frequency, thus enhancing efficiency and reducing costs.
Implementation Method 1
an ion sensitive membrane provided between the electrolyte solution and the solution to be tested
Implementation Method 2
an electrolyte solution enclosed in the casing
Data Source
Figure 1
Figure 2(a)~2(c)
Figure 3~4
AI summary
The present invention addresses the problem of improving both ion-selective electrode stability and adhesion between a sensitive film and a casing. This ion-selective electrode is characterized by being provided with: a sensitive membrane containing an ion-selective substance, a substrate, and a plasticizer; and a casing that holds the sensitive membrane, and by the casing material containing a substance having a solubility parameter (SP value) of 19.5 to 21.5.