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Patent Issued for Method of Forming Composite Materials Including Conjugated Materials Attached to Carbon Nanotubes Or Graphenes

August 13, 2014

By a News Reporter-Staff News Editor at Journal of Engineering -- From Alexandria, Virginia, VerticalNews journalists report that a patent by the inventors Zhai, Lei (Oviedo, FL); Liu, Jianhua (Orlando, FL); Zou, Jianhua (Orlando, FL); Chunder, Anindarupa (Orlando, FL), filed on November 12, 2013, was published online on July 29, 2014.

The patent's assignee for patent number 8790610 is University of Central Florida Research Foundation, Inc. (Orlando, FL).

News editors obtained the following quote from the background information supplied by the inventors: "Two carbon allotropes, carbon nanotubes (CNTs) and graphene, have attracted significant attention due to their remarkable mechanical, thermal, and electrical properties. In theory, the in-plane electrical conductivity of metallic single wall CNTs can be 1,000 times higher as compared to both silver and copper, and the tensile strength of a multiwalled CNT is expected to be in the range of 10-100 GPa. The potential applications of CNTs extend from nanoelectronics, to sensors, energy storage devices (fuel cells, batteries, and supercapacitors), photovoltaics, biomolecular imaging and detection, thermal management, and conductive nanocomposite.

"Graphene is a flat monolayer of carbon atoms tightly packed into a two dimensional (2D) honeycomb lattice. Electrons in graphene behave like massless relativistic particles, which contributes to very peculiar properties such as an anomalous quantum Hall effect and the absence of localization. Graphene has demonstrated a variety of intriguing properties including high electron mobility at room temperature (15,000 cm.sup.2/Vs) and superior mechanical properties (Young's modulus is 500 GPa.). Its potential applications range from single molecule gas detection, transparent conducting electrodes and field-effect devices to energy storage devices such as supercapacitors and lithium ion batteries.

"The effective utilization of CNTs and graphenes in composites and devices depends strongly on the ability to disperse them homogeneously in solvents and the matrix, and to functionalize their surfaces with target functional groups. However, it is challenging to achieve stable CNT and graphene dispersions in solvent media, as well as to functionalize their surfaces. The as-produced CNTs have a strong tendency to bundle together, and similarly graphenes tend to exist in the form of a graphite due to strong van der Waals interactions.

"Surface modification of CNT and graphene with small molecules or polymers is one way to attempt to increase their solubility and provide desired functionalities. The surface modification generally involves attaching functional groups to CNT/graphene surfaces through the formation of covalent bonds (covalent approaches) or non-covalent bonds (non-covalent approaches). Although the covalent approach is generally effective in functionalizing CNTs and graphenes, the covalent bonding disrupts the long range .pi. conjugation of the CNT, leading to degraded electrical properties and diminished mechanical strength.

"In contrast, non-covalent approaches can utilize multiple weak interactions such as .pi.-.pi. interactions, van der Waals interactions, and static charge interactions. Such non-covalent interactions avoid damage to the chemical structure, and allows the CNT or graphene to retain their electrical and mechanical properties. However, although significant effort has been invested in this pursuit, the commercial application of CNTs and graphene is still extremely limited, mainly due to the lack of a simple and versatile system to disperse and functionalize CNTs and graphenes."

As a supplement to the background information on this patent, VerticalNews correspondents also obtained the inventors' summary information for this patent: "Disclosed embodiments include methods of forming composite materials including supramolecular structures having at least partially conjugated materials attached to carbon nanotubes (CNTs) or graphenes. A conjugated material is dispersed with a solvent for the conjugated material together with a plurality of CNTs or graphene including structures having an outer surface to form a dispersion. The solvent is evaporated from the dispersion to yield a CNT or graphene composite material including a plurality of at least partially crystalline supramolecular structures having the conjugated material non-covalently secured to the outer surface of the CNT or the graphene including structure. The supramolecular structures have an average length which extends outward in a length direction from the outer surface of the CNT or graphene including structure, where the average length is greater than an average width of the supramolecular structures.

"Other disclosed embodiments include composite materials that include at least one CNT or a graphene comprising structure having an outer surface, and a plurality of at least partially crystalline supramolecular structures that include a conjugated material non-covalently secured to the outer surface of the CNTs or the graphene comprising structure. The conjugated material can be a conjugated homopolymer, a block copolymer that includes at least one conjugated block, a conjugated oligomer, or a conjugated non-polymeric or oligomeric material such as pentacene, tetracene, or hexacene, pyrene, perylene or porphyrine and similar compounds. The supramolecular structures extend outward from the outer surface of the CNTs or graphene comprising structures.

"Disclosed embodiments include electronic device comprising a plurality of electrodes, wherein a disclosed composite material is between the electrodes. In another embodiment, supramolecular structures provide a gate/channel region that connects to CNT arrays or graphene comprising structures that provide the source and drain electrodes to realize an organic field effect transistor (FET)."

For additional information on this patent, see: Zhai, Lei; Liu, Jianhua; Zou, Jianhua; Chunder, Anindarupa. Method of Forming Composite Materials Including Conjugated Materials Attached to Carbon Nanotubes Or Graphenes. U.S. Patent Number 8790610, filed November 12, 2013, and published online on July 29, 2014. Patent URL:

Keywords for this news article include: Fullerenes, Nanotechnology, Supramolecular, Carbon Nanotubes, Emerging Technologies, University of Central Florida Research Foundation Inc.

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Source: Journal of Engineering

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