Gregory Konesky (Hampton Bays, NY) earned U.S. Patent 7,749,478 for a method for the morphological control of carbon nanotubes
Konesky’s disclosure relates to morphological control of carbon nanotubes, to form shapes, including, inter alia, nanosprings, nanocoils and nanohooks of desired shape, diameter, chirality and /or pitch wherein a desired morphological design may be manipulated with spatially, sequential time varying electric fields formed by electrode arrays located and activated near the CNT growth substrate. These forms may be employed in a myriad of various applications, including, micro electromechanical systems and advanced microelectronic interconnects.
The disclosure relates to the morphological control of carbon nanotubes by the use of spatially sequential time varying field-directed synthesis of the carbon nanotubes. Carbon nanotubes (CNTs) may be designed or synthesized in a variety of morphologies, including coiled, hooked, spiraled, helical, geometric and irregular forms. These forms may be employed in a myriad of various applications, including, for example, micro electromechanical systems (MEMS) and advanced microelectronic interconnects.
Carbon nanotubes may be produced by any conventional method. Carbon nanotubes typically designed or synthesized by conventional methods form into a variety of morphologies simultaneously and are difficult to separate into particular formations. Morphologies may, to some extent, be selected by control of synthesis conditions. Direct current plasma enhanced chemical vapor deposition (PECVD) and chemical vapor deposition (CVD) can be performed by techniques well known to those of ordinary skill in the art to produce CNTs, and align nanotubes along the electric field.
Carbon nanotubes may be produced by any conventional method. Carbon nanotubes typically designed or synthesized by conventional methods form into a variety of morphologies simultaneously and are difficult to separate into particular formations. Morphologies may, to some extent, be selected by control of synthesis conditions. Direct current plasma enhanced chemical vapor deposition (PECVD) and chemical vapor deposition (CVD) can be performed by techniques well known to those of ordinary skill in the art to produce CNTs, and align nanotubes along the electric field.
The electric field along the edges of a substrate can have various orientations, which may cause CNTs grown in that area to also have differing orientations. The alignment is typically perpendicular to the surface on which the nanotubes are grown. CNTs can be formed or grown to include hooks on at least one end. However, these controls tend to be time-consuming and unreliable.
Carbon nanotubes may be designed or formed into programmed growth morphologies to produce a variety of CNT shapes and morphologies as desired via the use of spatially sequential time varying field-directed synthesis. The CNTs may be initially formed in an approximately straight shape by any conventional means. Hooks may then be formed on either one end or both ends of the straight CNTs by exposing the CNTs to an activated electric field or fields. Exposure to the electric fields can induce the CNTs to grow towards the negative charge of that field. In one embodiment, the orientation of the substrate with respect to the electric field may be varied or re-oriented to form and adapt CNT shapes.
Carbon nanotubes may be designed or formed into programmed growth morphologies to produce a variety of CNT shapes and morphologies as desired via the use of spatially sequential time varying field-directed synthesis. The CNTs may be initially formed in an approximately straight shape by any conventional means. Hooks may then be formed on either one end or both ends of the straight CNTs by exposing the CNTs to an activated electric field or fields. Exposure to the electric fields can induce the CNTs to grow towards the negative charge of that field. In one embodiment, the orientation of the substrate with respect to the electric field may be varied or re-oriented to form and adapt CNT shapes.
In an alternative embodiment, the electric field may be re-oriented with respect to the substrate on which the CNTs are grown to change or re-shape the carbon nanotubes. Yet another embodiment employs a fixed array of field-inducing electrodes, which can vary the electric fields sequentially in time and location to cause the CNTs to shift and change the direction of formation according to the location of the electric field. This sequentially varied field has the advantage of simplicity and control for implementing morphological changes.
CNTs of different morphologies may be employed in a myriad of ways. For example, CNT having hooks or hook-like structures on their ends may be used as a strong, effective VELCRO-like (hook and loop) structure with nano-structures that is not abrasive to surrounding materials. CNT coils can be used as nano-springs and in some cases, micro-springs for use in any environment that requires resistance to high temperatures or corrosiveness.
CNT coils can also be highly useful in micro electromechanical systems (MEMS) and advanced microelectronic interconnects due to their ideal combination of high strength and minute size. CNTs of any shape may be advantageously in micro fabrications of those and many additional systems, such as for example, high frequency circuitry, accelerometers, and research equipment such as scanning tunnel microscopes and polymerase chain reaction microsystems.
0 comments:
Post a Comment