Graphitic nanocomposites in solid state matrices and methods for making same

#The present invention is directed to graphitic nanocomposites in solid state matrices and methods for making same. The resulting graphitic nanocomposite can be a form of a free standing bulk; a thin film coating adhered to a substrate (such as glass or plastic) or a three-dimensional network by infiltrating into a porous substrate (such as paper, fabric/textile or thread).

#In previous works entitled “Thiation of Carbon Nanotubes and Composite Formation” (U.S. Pat. No. 7,713,508 B2) and “Antennas Based on a Conductive Polymer Composite and Methods for Production Thereof” (U.S. Pat. No. 8,248,305 B2), the formation of a highly conductive composite through tight networks of interwoven carbon nanotube bundles was demonstrated. Binding nanotubes into large, but tight bundles, dramatically alters the morphology and electronic transport dynamics of the composite. This enables the composite to carry higher levels of charge in the macroscale leading to conductivities as high as 1600 S/cm. When controlled and used appropriately, the interesting properties of these composites reveal their potential for practical device applications, such as improving the properties of an electromagnetic (EM) antenna/amplifier transducer. An electronic transducer was fabricated where the composite film can receive broadband radio waves up to GHz frequencies and convert them to measurable current. The benefit of this coating is that it can be used as an EM amplifier in the presence of other metals.

#In additional to carbon nanotubes, graphene has attracted much attention in the past few years. Graphene possesses unique electronic properties, such as the quantum hall effect in condensed-matter materials and excellent mobility of charge carriers due to its unique π-conjugated carbon monolayer 2D system. Based on these qualities, many researchers have focus on the development of graphene-based electronic devices. However, understanding of EM attenuation/amplification properties of graphenes or graphene oxides is still limited. By using liquid-phase exfoliation of graphite in common organic solvent such as N-methyl-2-pyrrolidone (NMP), graphene/graphene oxide dispersion can be produced with high-yield. Because of the strong π-π interactions, graphenes/graphene oxides are expected to process strong EM attenuation/amplification properties.

#For a more complete understanding of the present disclosure, and the advantages thereof, reference is now made to the following descriptions to be taken in conjunction with the accompanying drawings describing specific embodiments of the disclosure, wherein:

#FIG. 1 is an illustrative embodiment of a process to produce graphitic nanocomposites in solid state matrices;

#FIGS. 2a-2f show various multi-walled carbon nanotube (MWNT)/sol-gel mixtures dispersed in ethanol after heated stirring; and

#It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention, as claimed. In this application, the use of the singular includes the plural, the word “a” or “an” means “at least one”, and the use of “or” means “and/or”, unless specifically stated otherwise. Furthermore, the use of the term “including”, as well as other forms, such as “includes” and “included”, is not limiting. Also, terms such as “element” or “component” encompass both elements or components comprising one unit and elements or components that comprise more than one unit unless specifically stated otherwise.

#Methods and composition for making graphitic nanocomposites in solid state matrices are discussed herein. The present invention offers new compositions and methods for making graphitic nanocomposites in solid state matrices.

#In an illustrative nonlimiting embodiment, compositions and methods for making graphitic nanocomposites in solid state matrices comprise the following steps: selecting one or a mixture of specific graphitic nanomaterials, and functionalizing the graphitic nanomaterials. As a nonlimiting example, the graphitic nanomaterials may be single-walled carbon nanotube and may be functionalized by covalent bonding with a moiety similar to the building blocks of the solid state matrices. The functionalized graphitic nanomaterials are mixed with the building blocks of the solid state matrices. As a nonlimiting example, the functionalized graphitic nanomaterials may be mixed with sol-gel chemicals comprising at least an alkoxysilane or metal oxide precursor to form a homogeneous sol-gel/nanomaterial mixture. In some embodiments, optional intermediate steps may be desirable before formation of a three-dimensional network. For example, depending on the desired three-dimensional network, the sol-gel/nanomaterial mixture may be poured into a mold to form a free standing bulk, deposited on a flat substrate to form a thin film coating, infiltrated into a porous substrate, or the like to form the desired three-dimensional network. The solid state matrices may be formed by curing the functionalized graphitic nanomaterial and building blocks mixture at an elevated temperature, which in situ entraps and/or covalently links with the graphitic nanomaterials during the network growth process. For example, the sol gel and nanomaterial mixture may be cured after it has been poured into a mold, deposited on a substrate, infiltrated a porous substrate, or the like. As a nonlimiting example, the mixture may be cured at temperatures equal to or between 25 and 200° C. This process allows the nanomaterials to be introduced into the matrices homogeneously without forming problematic large aggregations.