Solid-State pH Sensor Gel Resists Process Pressure
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Solution Overview
Problem
pH sensors with liquid reference electrodes experience significant response fluctuations under positive process pressure due to disturbed ion diffusion, leading to measurement errors and instability, making them unsuitable for applications with varying pressures.
Innovation Solution
A solid-state reference gel is developed by mixing water, a buffer system, polyethylene glycol or its derivatives as a gelling agent, and a reference electrolyte salt, which is then subjected to Gamma irradiation to form a stable, biocompatible gel that resists process pressure without the need for internal pressure compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a liquid reference electrolyte is used in the reference electrode, then the sensor can be manufactured with simpler structure, but the sensor exhibits significant response fluctuations under positive process pressure
Solution Approach 1:
The patent changes the physical state of the reference electrolyte from liquid to solid gel form. This parameter change eliminates the response fluctuations caused by liquid electrolyte under pressure while maintaining the reference electrode's functionality. The solid gel state provides pressure resistance without requiring complex internal pressure compensation mechanisms.
Solution Approach 2:
The patent uses a composite gel material formed by mixing water, buffer system, polyethylene glycol (or its derivatives), and reference electrolyte salt. This composite material combines the beneficial properties of each component: water as solvent, buffer for pH stability, polyethylene glycol for gelling and pressure resistance, and reference electrolyte salt for ionic conductivity. The composite gel resolves the contradiction between simplicity and reliability.
2Reliability
If internal pressure is applied to the reference electrode to cancel external process pressure, then sensor response stability is improved, but device complexity and manufacturing difficulty increase significantly
Solution Approach 1:
The patent extracts and eliminates the need for internal pressure compensation mechanisms by using solid gel electrolyte. The gel's inherent solid-state structure provides natural pressure resistance, removing the disturbing element of complex pressure balancing systems while maintaining response stability under varying process pressures.
Solution Approach 2:
The patent replaces the mechanical pressure compensation system with a chemical/material solution. Instead of using mechanical means (internal pressure chambers, diaphragms, or active pressure balancing mechanisms), the solid gel electrolyte inherently resists pressure through its solid-state structure, substituting a mechanical system with a material property-based solution.
3Strength
If polyethylene glycol concentration is increased to improve gel strength and pressure resistance, then the gel's mechanical properties are improved, but the gelation time and processing difficulty increase
Solution Approach 1:
The patent uses polyethylene glycol at concentrations ranging from 2% to 90% wt%, allowing optimization between gel strength and processing ease. By selecting appropriate concentrations within this range, the patent achieves sufficient pressure resistance without excessive gelation time or processing difficulty, applying partial action rather than maximum concentration.
Solution Approach 2:
The patent changes parameters such as polyethylene glycol molecular weight (minimum average of 15,000) and concentration to optimize the balance between gel strength and processability. These parameter changes allow the gel to achieve adequate pressure resistance while maintaining reasonable gelation characteristics for manufacturing.
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 solid-state gel eliminates pressure-induced response fluctuations, ensuring accurate pH measurements across a wide range of pressures without additional mechanical complexity, and is suitable for hygienic applications due to its biocompatibility and sterilization properties.
Implementation Method 1
the mixture when subjected to Gamma irradiation forms the reaction product
Data Source
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AI summary
A solid state gel for use in a pH sensor comprises a reaction product of water, a buffer system for adjusting pH of the gel when in a liquid state, polyethylene glycol or its derivatives as a gelling agent and a salt wherein the water, the buffer, the polyethylene glycol and a reference electrolyte salt when mixed while in a liquid state form a mixture that was subjected to Gamma irradiation to form the reaction product. Also is disclosed the manufacturing of the solid state gel, a pH sensor comprising the gel and its production.