Efficient Selection of Carbon Nanotubes by Desired Properties
In the beginning powder form, carbon nanotubes (CNTs) have a wide range of physical dimensions and electrical properties at the level of individual CNTs. A number of researchers have tried various methods of selecting and manipulating (CNTs) produced in batch quantities. However, these processes do not select CNTs by specific dimensions, or select CNTs by conductivity (e.g. for use as semiconductors or as conductors). In addition, current methods of selecting CNTs have negative side effects in altering the structure and electrical properties of the CNTs.
Description of Technology
The CNT selection method includes a series of processes: sonication (breaking down bundled CNT powder into small bundles and individual CNT); centrifugation (CNT separation based on CNT size and density differences); filtering and CNT manipulation. A CNT deposition system is developed to manipulate CNTs precisely by dielectrophertic (DEP) forces. Different input voltages and frequencies attract different types of CNT. The invention holds promise for an effective, efficient, repeatable process for classification, manipulation, selection and filtering of CNTs with desired electrical properties and dimensional ranges.
- Specificity: The process can classify specific types of carbon nanotubes with specific dimensions and other selected physical properties.
- Precision: Process allows manipulation of individual carbon nanotubes which can be transfered to desired locations through a micro tip mounted on micro manipulators.
- Production efficiency: The process enables high yield and repeatable batch fabrication of CNTs to be used in CNT-based nano-devices. The process also eliminates the use of strong chemicals that can alter the structure of carbon nanotubes.
The above invention, with its potential for specificity and production efficiency in selecting CNTs with specified properties, lends itself to automated production and commercialized production of CNTs for use in commercial applications (e.g. manufacture of nanodevices). The invention has potential utility for fabricating nanodevices and for preparing nanotubes with desired properties for research institutions.
Patented US 8,293,086
Ning Xi, Wai Chiu King Lai, Uche Wejinya
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Michigan State University