Continuous Carbon Nanotube Membrane Filtration
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Solution Overview
Problem
Conventional methods for producing carbon nanotube membranes are discontinuous, limiting the quantity and length of buckypapers produced, making it difficult to achieve consistent quality and large-scale applications due to the need for frequent filter changes and limited filter dimensions.
Innovation Solution
A continuous method involving the formation of a suspension of nanoscale fibers, followed by filtration using a moving filter membrane, either static or dynamic, with the aid of vacuum or pressure, to produce a continuous membrane of aligned nanotubes, which can be impregnated with a liquid matrix material for solidification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If discontinuous filtration methods are used to produce nanotube membranes, then the filtration process can be completed with existing filter membranes, but the production quantity and membrane length are limited by filter dimensions requiring frequent filter changes
Solution Approach 1:
The patent implements continuous filtration by moving the filter membrane through the nanotube suspension in a continuous manner, allowing the filtration process to proceed without interruption. The filter membrane is continuously advanced through the suspension while nanotubes are deposited, eliminating the need to stop for filter changes and enabling production of membranes longer than the filter dimensions would normally permit.
Solution Approach 2:
The patent introduces dynamic movement of the filter membrane through the suspension, transforming the static filtration process into a dynamic one. The filter membrane is moved at controlled speeds through the suspension, allowing continuous deposition of nanotubes over extended periods and producing membranes of arbitrary length limited only by the duration of the process rather than filter size.
2Quantity of substance
If multiple filters are used to produce large quantities of buckypapers, then the production volume can be increased, but the process becomes more complex and costly
Solution Approach 1:
By implementing continuous filtration, a single filter membrane can produce large quantities of buckypaper over extended time periods. The continuous movement through the suspension allows one filter to generate substantial material output without requiring multiple filters to be deployed simultaneously or sequentially changed.
Solution Approach 2:
The dynamic movement of the filter membrane through the suspension enables a single filter to process large volumes of suspension and produce extensive membrane areas. The continuous advancement allows one filter to accomplish what would traditionally require multiple filters, simplifying the overall device configuration.
3Manufacturing precision
If discontinuous filtration is used, then the process can be performed with standard filtration equipment, but consistent product quality is difficult to ensure due to piece-by-piece production
Solution Approach 1:
The continuous filtration process maintains steady-state operating conditions throughout the deposition, ensuring uniform nanotube distribution and membrane properties across the entire product. The uninterrupted process eliminates variations between discrete production batches, guaranteeing consistent quality throughout the continuous membrane.
Solution Approach 2:
The controlled dynamic movement of the filter membrane through the suspension ensures uniform deposition conditions are maintained throughout the process. The consistent velocity and continuous exposure to the nanotube suspension result in homogeneous membrane formation, improving quality consistency while maintaining high productivity.
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
Enables the production of high-quality, continuous nanotube membranes of varying lengths and widths, facilitating their use in advanced applications such as thermal and electrical conducting devices, and overcoming the limitations of traditional methods by allowing for scalable and consistent production.
Implementation Method 1
filtering the suspension by moving a filter membrane through the suspension, such that the nanoscale fibers are deposited directly on the filter membrane as the fluid medium flows through the filter membrane
Implementation Method 2
the filtration step is conducted with the aid of vacuum to pull water through the filter membrane, applied pressure to press water though the filter membrane
Implementation Method 3
with the aid of vacuum or pressure, to produce a continuous membrane
Implementation Method 4
The suspension is subjected to sonication prior to the filtration step
Implementation Method 5
the filtration step is conducted within a magnetic field effective to align the nanoscale fibers
Data Source
AI summary
Methods and devices are provided for the continuous production of a network of nanotubes or other nanoscale fibers. The method includes making a suspension of nanoscale fibers dispersed in a liquid medium, optionally with surfactant and/or sonication, and filtering the suspension by moving a filter membrane through the suspension, such that the nanoscale fibers are deposited directly on the filter membrane as the fluid medium flows through the filter membrane, thereby forming a continuous membrane of the nanoscale fibers. The deposition of the nanoscale fibers can occur when and where the filter membrane moves into contact with a static, porous filter element or a dynamic, porous filter element. The filtering can be conducted within a magnetic field effective to align the nanoscale fibers, and/or with the aid of vacuum to pull water through the filter membrane, applied pressure to press water though the filter membrane, or a combination thereof.