Gas Permeable Electrode via Polymer Template Pores
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Solution Overview
Problem
Existing gas-permeable electrodes for sensors are limited by low permeability, which restricts response time due to dense metal-based conductive materials, and current methods for creating diffusion channels are destructive, size-precise, and chemically non-selective, often damaging soft or porous sensing materials.
Innovation Solution
A method involving coating a sensing material with a gas-permeable polymer, depositing an electrically conductive metal layer over polymer bumps or islands, and creating cracks, voids, or pores through the interaction of the metal with a soluble, flexible polymer, allowing for enhanced gas diffusion without damaging the sensing material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dense metal-based conductive materials are used as electrodes, then electrical conductivity is improved, but gas permeability deteriorates
Solution Approach 1:
The patent applies porous metal layers instead of dense metal electrodes. The porous structure allows gas molecules to diffuse through the electrode while maintaining electrical conductivity through the metal framework. This resolves the contradiction by enabling both gas permeability and electrical conductivity simultaneously.
Solution Approach 2:
The patent uses composite electrode structures combining metal components with porous characteristics. These composite materials integrate the electrical conductivity of metals with the gas permeability of porous structures, creating a material that satisfies both requirements without compromise.
2Object-generated harmful factors
If destructive techniques such as template digestion with harsh chemicals or plasma etching are used to create diffusion channels, then gas permeability is improved, but the sensing material is damaged
Solution Approach 1:
The patent introduces a sacrificial polymer layer as an intermediary material deposited over the sensing material. This polymer layer serves as a temporary template that guides the formation of diffusion channels without directly contacting or damaging the sensitive sensing material. After creating the desired pore structure, the polymer is removed, leaving clean diffusion channels.
Solution Approach 2:
The patent performs preliminary deposition of a polymer layer before creating diffusion channels. This preliminary structure is built carefully over the sensing material, and only after this protective layer is in place are the diffusion channels formed by removing the polymer. This preliminary action prevents direct exposure of the sensing material to damaging etching processes.
3Manufacturing precision
If top patterned masks/templates are assembled before metal deposition, then pattern precision is improved, but manufacturing complexity increases and physical limits are exceeded
Solution Approach 1:
The patent extracts the pattern-defining function from complex assembled masks and templates, replacing them with a simpler deposited polymer layer. The polymer pattern is formed directly through deposition processes without requiring separate mask assembly, thereby reducing manufacturing complexity while maintaining pattern precision through the inherent control of deposition techniques.
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
This approach results in a gas-permeable electrode with improved diffusion rates and reduced damage to sensitive materials, enabling faster and more accurate gas detection while maintaining the integrity of the sensing material.
Implementation Method 1
Gas permeable electrodes are essential to facilitate the diffusion of gases into a porous gas/liquid sensing material intercalated within a capacitor sensor device
Implementation Method 2
The resulting metal electrode has cracks, voids, discontinuities, interstices, holes or pores caused by the interaction of the deposited metal layer with the bumps of the second polymer (e.g., due to the expansion/contraction of a flexible, porous, and soluble material such as the second polymer within a rigid and insoluble coating or shell of the deposited metal layer, and the differences of the expansion coefficient of the two different materials)
Implementation Method 3
In some embodiments, the assembly is exposed to moisture (e.g., in the atmosphere or ambient air) to cause swelling of the bumps or blobs of the second polymer, and to promote larger cracks, voids, discontinuities, interstices, holes or pores in the metal electrode
Data Source
AI summary
The disclosure provides a gas permeable electrode and method for making the electrode to create diffusion pathways (or pores) in the metal electrode in a manner that is not destructive to delicate or soft sensing material. A first polymer, which is gas-permeable, is applied as a continuous coating over a surface of the sensing material. A second polymer that is immiscible with the first polymer is applied over a surface of the first polymer (e.g., spray-dry deposition of the second polymer) to form a micro-pattern or a polymeric template. The incompatibility/immiscibility between the first polymer and the second polymer leads to segregation of the second polymer into a pattern of discontinuous bumps, dots, islands or blobs on top of the first polymer. The porous electrode comprises at least one layer of an electrically conductive metal that is deposited over the first and second polymers. Bumps of the second polymer promotes small cracks or voids in the metal electrode layer that enable fast diffusion of analytes through the electrode.