Crown Ether Ion-Sensitive Membrane Durability
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Solution Overview
Problem
Conventional ion-sensitive membranes used in ion-selective electrodes have insufficient durability when repeatedly used, leading to a loss of ion selectivity and performance.
Innovation Solution
An ion-sensitive substance with a crown ether structure containing an alkoxysilyl group is developed, which forms a siloxane bond upon hydrolysis, providing stability and maintaining ion selectivity even after repeated use. The substance is produced by dissolving an alkali metal salt or Group 2 element salt in a liquid with a first compound having an epoxy group and an alkoxysilyl group, followed by cyclic polymerization and immersion in water to form a durable ion-sensitive membrane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional ion-sensitive membranes are prepared by mixing ion-sensitive substance with plasticizer in membrane support, then the membrane can be easily manufactured, but the durability is insufficient when repeatedly used
Solution Approach 1:
The patent uses a composite material system consisting of polyurethane polymer matrix combined with crown ether ion-sensitive substance and silane coupling agent. This composite structure provides both mechanical integrity for ease of manufacture and chemical stability for improved durability during repeated use as ion-selective electrode
Solution Approach 2:
The patent modifies the chemical parameters of the membrane by introducing silane coupling agents that form siloxane bonds with the polyurethane matrix. This parameter change in the molecular structure enhances the cross-linking density and chemical resistance, thereby improving durability while maintaining manufacturability
2Productivity
If conventional ion-sensitive membranes are used repeatedly, then manufacturing cost is reduced, but ion selectivity and performance are lost
Solution Approach 1:
The patent applies local quality enhancement by concentrating the crown ether ion-sensitive substance within the polyurethane matrix at specific regions where ion recognition is needed. The silane coupling agents are localized at the interface between the membrane and underlying layers, providing targeted adhesion strength that maintains ion selectivity during repeated use
Solution Approach 2:
The patent performs preliminary chemical modification by pre-forming siloxane bonds between the silane coupling agent and polyurethane matrix before final membrane assembly. This preliminary action creates a stable chemical framework that preserves ion selectivity throughout the service life of the electrode
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 ion-sensitive membrane exhibits improved durability and maintains high ion selectivity and potential response, with a suitable elastic modulus, making it suitable for repeated use as an ion-selective electrode.
Implementation Method 1
a part or all of the alkoxysilyl groups in the crown ether structure may be hydrolyzed to form a silanol group
Data Source
AI summary
An ion-sensitive substance containing a crown ether structure composed of a repeating unit represented by formula (a): —CR1R2—CR3X—O— . . . (a) (in the formula, X is an organic group having an alkoxysilyl group at a terminal, and R1, R2 and R3 are each a hydrogen atom or a hydrocarbon group), and a part or all of the alkoxysilyl groups in the crown ether structure may be hydrolyzed to form a silanol group.