Carbon-based nanomaterials such as carbon nanotubes (CNTs), fullerenes and graphene are receiving great attention today due to their unique physical properties. A new study explores the potential of hybrid nanostructures and introduces a new porous graphene CNT hybrid structure with remarkable thermal and mechanical properties.
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The study shows how the remarkable characteristics of the new CNT graphene hybrid structures could be modified by slightly modifying the inherent geometric arrangement of CNTs and graphene, as well as various fillers.
The ability to precisely control the thermal conductivity and mechanical strength of graphene CNT hybrid structures makes it a potentially suitable candidate for various application areas, especially in advanced aerospace manufacturing where weight and strength are critical.
Carbon Nanostructures: CNTs, Graphene, Fullerenes
Carbon nanostructures and hybrids of multiple carbon nanostructures have recently been investigated as potential candidates for numerous sensing, photovoltaic, antibacterial, energy storage, fuel cell, and environmental improvement applications. .
The most important carbon-based nanostructures in research seem to be CNTs, graphene and fullerene. These structures exhibit unique thermal, mechanical, electronic and biological properties due to their extremely small size.
Structures that measure in the sub-nanometer range behave according to the particular laws of quantum physics, and therefore can be used to exploit non-intuitive phenomena such as quantum tunneling, quantum superposition, and quantum entanglement.
CNTs are carbon tubes that measure only a few nanometers in diameter. CNTs display notable electrical conductivity and some are semiconductor materials.
CNTs also have high tensile strength and thermal conductivity due to their nanostructure and the strength of covalent bonds formed between carbon atoms.
CNTs are potentially valuable materials for electronics, optics and composite materials, where they could replace carbon fibers in the next few years. Nanotechnology and materials science also use CNTs in research.
Graphene is an allotrope of carbon that is shaped into a single layer of carbon atoms arranged in a two-dimensional lattice structure composed of hexagonal shapes. Graphene was first isolated in a series of groundbreaking experiments by University of Manchester, UK, scientists Andrew Geim and Konstantin Novoselov in 2004, which won them the Nobel Prize in Physics in 2010 .
Over the next several decades, graphene has evolved into a useful nanomaterial with exceptionally high tensile strength, transparency, and electrical conductivity, leading to many and varied applications in electronics, sensing and other advanced technologies.
A fullerene is another allotrope of carbon that has been known for some time. Its molecule consists of carbon atoms connected by single and double bonds to form a mesh, which can be closed or partially closed. The mesh is fused with rings of five, six or seven atoms.
Fullerene molecules can be hollow spheres, ellipsoids, tubes, or a number of other shapes and sizes. Graphene could be considered an extreme member of the fullerene family, although it is considered a member of its own class of materials.
Along with a lot of research invested in understanding and characterizing these carbon nanostructures in isolation, scientists are also exploring the properties of hybrid nanostructures that combine two or more nanostructure elements into a single material.
For example, foam materials have tunable properties that make them suitable for practical applications such as the design of sandwich structures, the design of biocompatibility, and the design of high-strength, low-weight structures.
Carbon-based nanofoams have also been used in medicine, examining bone damage and serving as the basis for replacement bone tissue.
Carbon-based cellular structures are produced by both chemical vapor deposition (CVD) and solution processing. Spark Plasma Sintering (SPS) methods are also being implemented to utilize graphene for biological and medical applications.
As a result, scientists have looked for ways to make three-dimensional carbon foams structurally stable. Research suggests that stable junctions between different types of structures (CNTs, fullerene and graphene) must be formed for this material to be stable enough for widespread application.
New research on hybrid nanostructures
New research from mechanical engineers at Istanbul Technical University in Turkey shows a new hybrid nanostructure formed by chemical bonding.
The porous structures of graphene CNTs have been made by arranging graphene around CNTs in nanoribbons. The different geometric arrangement of the graphene nanoribbon layers around the CNTs (square, hexagonal and diamond patterns) led to the observation of different physical properties in the material, suggesting that this geometric rearrangement could be used to refine the new structure.
The study was published in the journal Physica E: Low-dimensional systems and nanostructures in 2022.
The researchers found that structures with inserted fullerenes, for example, exhibited significant stability and compressive strength without sacrificing tensile strength. The geometric arrangement of the carbon nanostructures also had a significant effect on their thermal properties.
The researchers said that these new hybrid nanostructures have significant advantages, especially for the aerospace industry. Nanoarchitectures with these hybrid structures can also be used in hydrogen storage and nanoelectronics.
References and further reading
Belkin, A., A. Hubler and A. Bezryadin (2015). Self-assembled oscillating nano-structures and the principle of maximum entropy production. Scientific reports. doi.org/10.1038/srep08323
Degirmenci, U., and M. Kirca (2022). Carbon-based nano-lattice hybrid structures: Mechanical and thermal properties. Physica E: Low-dimensional systems and nanostructures. doi.org/10.1016/j.physe.2022.115392
Geim, AK (2009). Graphene: status and prospects. Science. /doi.org/10.1126/science.1158877
Geim, AK and KS Novoselov (2007). The rise of graphene. Natural materials. doi.org/10.1038/nmat1849
Monthioux, M., and VL Kuznetsov (2006). Who should take credit for the discovery of carbon nanotubes? Carbon. doi.org/10.1016/j.carbon.2006.03.019