Perforated Graphene Sheets for Scalable Filtration
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Solution Overview
Problem
Current methods for forming perforations in graphene sheets for filtration applications are limited in scalability and precision, particularly in creating macroscale sheets with controlled perforation patterns and surface coverage by non-graphenic carbon-based materials.
Innovation Solution
The development of macroscale sheets comprising single or multilayer graphene with a non-graphenic carbon-based material, where the sheets are treated using ion beam or UV-oxygen exposure to create controlled perforations, allowing for greater than 10% surface coverage and precise control over perforation density and size, enabling applications such as filtration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If mechanical exfoliation is used to prepare graphene, then high electrical and thermal conductivity are achieved, but macroscale sheet production is limited
Solution Approach 1:
The patent replaces mechanical exfoliation with chemical vapor deposition (CVD) followed by oxygen plasma treatment. This substitution enables macroscale graphene sheet production while maintaining the desired electrical and thermal conductivity properties, resolving the contradiction between quantity and ease of manufacture.
Solution Approach 2:
The patent changes the preparation parameters by using CVD growth conditions and oxygen plasma exposure to create controlled perforations. This parameter change enables scalable macroscale sheet production with controlled surface coverage (10-80%) while preserving conductivity, addressing the scalability limitation of mechanical exfoliation.
2Reliability
If oxygen plasma treatment is applied to create perforations, then selective permeability is improved, but manufacturing precision control is challenging
Solution Approach 1:
The patent employs controlled oxygen plasma treatment parameters (exposure time, power, pressure) that provide feedback control over perforation formation. By adjusting these parameters, the process achieves reliable selective permeability while maintaining precise control over perforation density and surface coverage within the 10-80% range.
Solution Approach 2:
The patent uses parameter changes in the oxygen plasma treatment (varying power, exposure time, and oxygen flow rate) to precisely control the perforation formation process. This enables simultaneous achievement of reliable selective permeability and precise manufacturing control over perforation characteristics.
3Reliability
If high surface coverage with non-graphenic carbon-based material is achieved, then filtration performance is enhanced, but electrical conductivity is reduced
Solution Approach 1:
The patent applies local quality by creating controlled perforations with non-graphenic carbon-based material coverage limited to 10-80% of the surface. This localized treatment enhances filtration performance in the perforated regions while preserving electrical conductivity in the remaining graphene areas, resolving the contradiction between filtration performance and conductivity.
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 enables the creation of graphene-based materials with controlled perforations suitable for filtration, offering improved scalability and precision in macroscale sheets, enhancing their selective permeability and performance in various applications.
Implementation Method 1
exposure of the sheet to ions
Implementation Method 2
exposure of the sheet to ions characterized by an ion energy ranging from 10 eV to 100 keV and a fluence ranging from 1×10^13 ions/cm² to 1×10^21 ions/cm² may produce perforations
Implementation Method 3
exposure of the sheet to ultraviolet radiation and an oxygen containing gas
Implementation Method 4
UV-oxygen treatment may involve exposure to light from 150 nm to 300 nm and intensity from 10 to 100 mW/cm² or 100 to 1000 mW/cm² at 6 mm distance for a time from 60 to 600 seconds
Implementation Method 5
thermal treatment may include heating to a temperature from 200° C. to 800° C. at a pressure of 10^-7 torr to atmospheric pressure for a time of 2 hours to 8 hours
Data Source
AI summary
Sheets of graphene-based material comprising single layer graphene and suitable for formation of a plurality of perforations in the single layer graphene are provided. In an aspect, the sheets of graphene-based material are formed by chemical vapor deposition followed by one or more conditioning steps. In a further aspect, the sheets of graphene-based material include non-graphenic carbon-based material and may be characterized the amount, mobility and/or volatility of the non-graphenic carbon-based material.