Flake Size Separation via Gas Bubble Percolation
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Solution Overview
Problem
Current methods for producing two-dimensional nano flake materials, such as graphene, struggle with achieving a narrow size distribution, leading to inconsistent material quality and limited industrial acceptance due to the inability to efficiently separate flakes by lateral size, resulting in compromised product performance and high production costs.
Innovation Solution
A method involving the redistribution of flake materials in a liquid dispersion using percolating gas bubbles, where larger flakes are propelled upwardly, allowing for the separation of flake fractions by vertical level, thereby achieving a narrower size distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mechanical impact is used to exfoliate bulk crystals into single atomic layers, then single layer flakes can be obtained, but the lateral size of flakes is limited to the size of mother single crystal and flakes are broken into smaller pieces
Solution Approach 1:
The bulk crystal is segmented into multiple single atomic layer flakes through mechanical impact and chemical intercalation. The segmentation process creates numerous thin flakes from the bulk material, achieving single-layer thickness while the subsequent flotation process separates these segmented flakes by their lateral size dimensions.
Solution Approach 2:
The invention transitions from two-dimensional lateral size control to three-dimensional vertical separation. By using density differences in a liquid medium and applying centrifugal force, flakes are separated along the vertical axis according to their lateral size, effectively adding a vertical dimension to the size control problem.
2Manufacturing precision
If chemical intercalation and ultrasonication are used to exfoliate graphite layers, then single sheets of graphene can be obtained, but the resulting flakes have diverse thickness and lateral size
Solution Approach 1:
A liquid medium serves as an intermediary between the graphite bulk crystal and the final separated flakes. Chemical intercalation agents penetrate the graphite layers in this liquid medium, causing controlled exfoliation. The liquid medium then allows density-based separation of the exfoliated flakes by lateral size through centrifugal or gravitational forces.
Solution Approach 2:
The invention changes physical parameters (density, centrifugal force, liquid viscosity) to control the separation process. By adjusting these parameters, flakes of different lateral sizes and thicknesses can be separated into distinct size fractions, transforming a heterogeneous mixture into uniform size distributions.
3Ease of manufacture
If no separation method is applied, then production cost is reduced, but material quality is inconsistent due to diverse flake size mixture
Solution Approach 1:
The invention uses hydraulic principles by employing liquid media and centrifugal force to separate flakes by size. This physical separation method avoids complex mechanical sorting equipment, maintaining relatively low production costs while achieving consistent material quality through density-based flotation and centrifugation.
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 technique effectively separates flakes into fractions with reduced size variance, enabling the production of well-controlled, high-quality two-dimensional materials with specific size distributions, addressing the limitations of existing methods and reducing production costs.
Implementation Method 1
percolating gas bubbles upwardly through the dispersion, for a time sufficient to allow the flake material to redistribute itself in the liquid with larger sized flakes higher up in the liquid and smaller sized flakes lower down in the liquid
Data Source
AI summary
The present disclosure provides a method for redistributing a flake material, in particular a two-dimensional nano flake material, into at least two flake size fractions, each of which having smaller flake size variance than the flake material. The method comprises providing a dispersion of the flake material in a liquid, wherein the flake material is not atomized in the liquid, arranging the dispersion in a container, percolating gas bubbles upwardly through the dispersion, for a time sufficient to allow the flake material to redistribute itself in the liquid with larger sized flakes higher up in the liquid and smaller sized flakes lower down in the liquid, and extracting at least one of the flake fractions from a limited vertical level of the container.