Graphene Membrane Plasma Etching Pore Control
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Solution Overview
Problem
Existing methods for fabricating graphene membranes with nanopores face challenges in controlling pore size and porosity, leading to suboptimal performance in gas separation applications.
Innovation Solution
A method involving exposure of a non-porous 2D film to a plasma comprising reactive gases, such as oxygen and argon, to create nanopores with controlled size distribution and porosity, utilizing inorganic oxides or nitrides as deposited components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If graphene is made porous through artificial pore fabrication (etching), then gas permeability is improved, but pore size control and porosity uniformity deteriorate
Solution Approach 1:
The patent introduces an intermediary layer (such as a sacrificial layer or template) that mediates the pore formation process. This intermediary structure enables controlled pore fabrication by serving as a precursor that defines pore locations and sizes before being removed or transformed, thereby achieving both high permeability and precise pore size control
Solution Approach 2:
The patent employs parameter changes in the etching process, such as controlling etch depth, etch rate, plasma power, gas flow rates, and treatment time, to precisely regulate pore size and distribution. By optimizing these parameters, the method achieves narrow pore size distribution while maintaining high gas permeability
2Reliability
If pore size is reduced to increase selectivity, then gas separation selectivity is improved, but gas flow rate (permeance) deteriorates
Solution Approach 1:
The patent applies local quality by creating uniform nanopores with precise size control across the membrane surface. This uniformity ensures that each pore contributes optimally to both selectivity and permeance, avoiding the trade-off that occurs with irregular pore distributions where some pores may be too small (reducing flow) or too large (reducing selectivity)
Solution Approach 2:
The patent may employ composite structures combining graphene with other materials or multi-layer configurations that enhance both selectivity and permeance. The composite approach allows optimization of pore characteristics while maintaining structural integrity and gas transport properties
3Manufacturing precision
If conventional etching methods are used for pore fabrication, then pore formation is achieved, but scalability and cost-effectiveness deteriorate
Solution Approach 1:
The patent replaces mechanical drilling or focused ion beam methods with plasma-based or chemical etching processes. These alternative methods enable batch processing and scaling to larger membrane areas while maintaining precise pore size control, thereby improving both manufacturability and cost-effectiveness
Solution Approach 2:
The patent develops a universal pore fabrication method that can be applied to various graphene membrane configurations and scales. The method uses commonly available materials and equipment, making it adaptable from laboratory-scale to industrial-scale production without requiring specialized facilities
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 method achieves graphene membranes with high porosity and narrow pore size distribution, enhancing gas separation efficiency by balancing permeance and selectivity.
Implementation Method 1
exposing said non-porous 2D film to a plasma comprising reactive gases, such as oxygen and argon, to create nanopores
Implementation Method 2
wherein said plasma comprises components suitable to deposit an inorganic oxide or inorganic nitride on said 2D film
Data Source
Figure 1A~1E
Figure 2A~2E
AI summary
The present invention concerns a method for producing a nanoporous 2D film, for example a graphene membrane. The method comprises exposing the non-porous 2D film to a reactive plasma and etching the 2D film so as to provide said nanoporous 2D film. In an embodiment, the method is a two-step method, comprising the initial deposition, by sputtering, of a protective layer comprising an inorganic oxide or nitride, before etching the 2D film. The nanoporous 2D films are useful for gas-separation.