Substrate-Free Flame Synthesis of Carbon Films on Liquid Surfaces
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Solution Overview
Problem
Existing methods for producing carbon-based films, particularly graphene, suffer from the formation of amorphous carbon impurities and are not scalable for large-area production, especially when using flame synthesis.
Innovation Solution
A novel flame synthesis method that directs a flame or plasma at a liquid surface, using a burner with varying flow velocity and distance to produce carbon-based films without a solid substrate, allowing for the deposition of pyrolysis vapors on the liquid surface, which can be quenched to form films with controlled characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If flame synthesis is used to grow graphene on a substrate, then carbon-based films can be produced, but amorphous carbon impurities are formed along with the graphene
Solution Approach 1:
The patent introduces a liquid surface (water or alcohol) as an intermediary medium between the flame and the collection surface. This liquid surface serves as a mediator that selectively absorbs graphitic carbon while rejecting amorphous carbon impurities, thereby purifying the graphene product during the deposition process itself
Solution Approach 2:
The patent changes the physical state of the substrate from solid to liquid, and further controls the temperature parameters by adjusting the distance between the flame and liquid surface. This parameter change enables selective deposition where graphitic carbon condenses on the liquid surface while amorphous carbon remains in the gas phase or is burned off
2Manufacturing precision
If conventional substrate-based methods are used for graphene production, then films can be grown, but the process is not readily scalable for large-area production
Solution Approach 1:
The patent transitions from two-dimensional growth on a solid substrate surface to three-dimensional utilization of a liquid volume that can be easily scaled. The liquid surface provides a large, easily expandable area for deposition, and the liquid medium itself can be circulated or replaced to enable continuous large-area production
Solution Approach 2:
The liquid surface serves multiple functions simultaneously: it acts as a substrate for deposition, a temperature control medium, an impurity filter, and a easily scalable platform. This multi-functionality eliminates the need for separate substrate preparation, heating, and cleaning steps that limit scalability in conventional methods
3Manufacturing precision
If flame synthesis parameters are adjusted to improve film quality, then film characteristics can be controlled, but the process complexity increases
Solution Approach 1:
The liquid surface automatically performs temperature regulation and impurity separation functions without requiring additional complex equipment. The natural properties of the liquid (heat capacity, surface tension, volatility) are harnessed to self-regulate the deposition process, reducing the need for sophisticated control systems
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 enables the production of substrate-free carbon-based films with varying thicknesses from nanometers to micrometers, avoiding amorphous impurities and facilitating scalable, large-area production with controlled film properties.
Implementation Method 1
reacting an oxidizer and a fuel in a burner with the flame directed at a liquid surface
Implementation Method 2
utilizing globally-rich combustion, a fraction of the hydrocarbon reactant generates the requisite elevated temperatures
Implementation Method 3
the pyrolysis vapors are carried by the flow and directed onto the liquid surface where they are quenched to form films
Implementation Method 4
the pyrolyzed precursor species exiting the burner are quenched to generate nanostructured particles by a vapor condensation mechanism
Data Source
AI summary
Methods for the production of films, particularly carbon-based films, based on gas-phase deposition on a liquid surface, and the products fabricated by the methods are provided.