Carbon Nanotube Yarn Joining for Continuous Length Fabrication
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Solution Overview
Problem
The existing methods for fabricating carbon nanotube yarns are limited by the diagonal length of the super-aligned carbon nanotube array, which restricts the yarn's length to approximately 4 inches, making it unsuitable for mass production and various applications requiring longer lengths.
Innovation Solution
A method involving the sequential pulling and joining of carbon nanotube structures from multiple arrays using a tool, followed by treatment with an organic solvent to form a continuous carbon nanotube yarn of desired length, allowing for arbitrary length extension and improved properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If carbon nanotube yarn is derived from a single super-aligned carbon nanotube array, then the fabrication process is simple, but the yarn length is limited to approximately 4 inches
Solution Approach 1:
The carbon nanotube yarn fabrication process is segmented into multiple stages: growing carbon nanotube arrays on separate substrates, pulling out individual structures from each array, and joining them end-to-end. This segmentation allows the yarn length to exceed the diagonal length of any single array by combining multiple shorter segments into a longer continuous structure.
Solution Approach 2:
The invention transitions from a single-dimensional constraint (yarn length limited by array diagonal) to a multi-dimensional solution by arranging multiple arrays in space and connecting them sequentially. The yarn length is no longer constrained by a single array's dimensions but can extend across multiple arrays arranged in a sequence, effectively adding a temporal dimension to the length extension process.
2Productivity
If the yarn length is extended beyond single array limitations, then mass production capability improves, but the fabrication process complexity increases
Solution Approach 1:
Carbon nanotube arrays are pre-grown on multiple substrates before the yarn fabrication process. This preliminary action allows the arrays to be prepared independently and simultaneously, and the pulling-out process can then proceed by sequentially extracting structures from each pre-prepared array, improving overall productivity while managing complexity through staged preparation.
Solution Approach 2:
The carbon nanotube structures join to each other through van der Waals attractive force when brought into contact, without requiring external bonding mechanisms. This self-service joining mechanism simplifies the fabrication process by eliminating the need for complex bonding equipment or additional joining steps, thereby improving productivity without proportionally increasing process complexity.
3Length of moving object
If carbon nanotube structures are joined end to end, then the yarn length increases, but the joining precision requirement increases
Solution Approach 1:
The van der Waals attractive force acts as an intermediary mechanism that automatically aligns and bonds carbon nanotube structures when they come into contact. This natural attractive force provides self-alignment during the joining process, reducing the precision requirements for manual or mechanical positioning compared to methods requiring active bonding mechanisms.
Solution Approach 2:
The invention replaces complex mechanical bonding systems with a simpler approach based on van der Waals forces. Instead of using mechanical fasteners, adhesives, or welding equipment, the carbon nanotube structures are joined through their inherent intermolecular attractive forces, significantly reducing the manufacturing precision requirements for the joining process.
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 production of carbon nanotube yarns with superior mechanical strength, thermal and electrical conductivity, and reduced coefficient of friction, suitable for diverse applications such as cables and printed circuit boards, without length limitations.
Implementation Method 1
A carbon nanotube yarn includes a plurality of carbon nanotube bundles that are joined end to end by van der Waals attractive force
Data Source
AI summary
A method for fabricating a carbon nanotube yarn includes providing a plurality of carbon nanotube arrays; pulling out, by using a tool, a first carbon nanotube structure from one of the carbon nanotube arrays; pulling out a subsequent carbon nanotube structure from another one of the carbon nanotube arrays; joining a leading end of the subsequent carbon nanotube structure to a trailing portion of the carbon nanotube structure already formed by contacting the leading end of the subsequent carbon nanotube structure with the trailing portion of the already-formed carbon nanotube structure, with the contact occurring along a common lengthwise direction of the two carbon nanotube structures, thereby forming a lengthened carbon nanotube structure; repeating the pulling and the joining until the lengthened carbon nanotube structure has a desired length; and treating the lengthened carbon nanotube structure with an organic solvent.