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A carbon nanotube (CNT) is a tube made of carbon with a diameter in the nanometre range (nanoscale). They are one of the allotropes of carbon. Two broad classes of carbon nanotubes are recognized:
A ceramic is any of the various hard, brittle, heat-resistant, and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain, and brick.
Thermoelectric materials show the thermoelectric effect in a strong or convenient form.
Nanoelectromechanical systems (NEMS) are a class of devices integrating electrical and mechanical functionality on the nanoscale. NEMS form the next logical miniaturization step from so-called microelectromechanical systems, or MEMS devices. NEMS typically integrate transistor-like nanoelectronics with mechanical actuators, pumps, or motors, and may thereby form physical, biological, and chemical sensors. The name derives from typical device dimensions in the nanometer range, leading to low mass, high mechanical resonance frequencies, potentially large quantum mechanical effects such as zero point motion, and a high surface-to-volume ratio useful for surface-based sensing mechanisms. Applications include accelerometers and sensors to detect chemical substances in the air.
Nanocomposite is a multiphase solid material where one of the phases has one, two or three dimensions of less than 100 nanometers (nm) or structures having nano-scale repeat distances between the different phases that make up the material.
Carbon nanotubes (CNTs) are cylinders of one or more layers of graphene (lattice). Diameters of single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs) are typically 0.8 to 2 nm and 5 to 20 nm, respectively, although MWNT diameters can exceed 100 nm. CNT lengths range from less than 100 nm to 0.5 m.
Composite gear housing refers to the use of composite materials to enclose the components of motor transmissions. Fiber reinforced composite materials are used primarily for weight reduction. Carbon fiber reinforced plastic material is commonly used in the aerospace and automotive industries.
Solid is one of the four fundamental states of matter along with liquid, gas, and plasma. The molecules in a solid are closely packed together and contain the least amount of kinetic energy. A solid is characterized by structural rigidity and resistance to a force applied to the surface. Unlike a liquid, a solid object does not flow to take on the shape of its container, nor does it expand to fill the entire available volume like a gas. The atoms in a solid are bound to each other, either in a regular geometric lattice, or irregularly. Solids cannot be compressed with little pressure whereas gases can be compressed with little pressure because the molecules in a gas are loosely packed.
Exfoliated graphite nano-platelets (xGnP) are new types of nanoparticles made from graphite. These nanoparticles consist of small stacks of graphene that are 1 to 15 nanometers thick, with diameters ranging from sub-micrometre to 100 micrometres. The X-ray diffractogram of this material would resemble that of graphite, in that the 002 peak would still appear at ~26o 2 theta. However, the peak would appear considerably smaller and broader. These features indicate that the interplanar distance in exfoliated graphite is similar to that of the parent graphite, but the stack size is small. Since xGnP is composed of the same material as carbon nanotubes, it shares many of the electrochemical characteristics, although not the tensile strength. The platelet shape, however, offers xGnP edges that are easier to modify chemically for enhanced dispersion in polymers.
The term "smart structures" is commonly used for structures which have the ability to adapt to environmental conditions according to the design requirements. As a rule, the adjustments are designed and performed in order to increase the efficiency or safety of the structure. Combining "smart structures" with the "sophistication" achieved in materials science, information technology, measurement science, sensors, actuators, signal processing, nanotechnology, cybernetics, artificial intelligence, and biomimetics, one can talk about Smart Intelligent Structures. In other words, structures which are able to sense their environment, self-diagnose their condition and adapt in such a way so as to make the design more useful and efficient.
A carbon nanothread is a sp3-bonded, one-dimensional carbon crystalline nanomaterial. The tetrahedral sp3-bonding of its carbon is similar to that of diamond. Nanothreads are only a few atoms across, more than 300,000 times thinner than a human hair. They consist of a stiff, strong carbon core surrounded by hydrogen atoms. Carbon nanotubes, although also one-dimensional nanomaterials, in contrast have sp2-carbon bonding as is found in graphite. The smallest carbon nanothread has a diameter of only 0.2 nanometers, much smaller than the diameter of a single-wall carbon nanotube.
Nanocomposite hydrogels are nanomaterial-filled, hydrated, polymeric networks that exhibit higher elasticity and strength relative to traditionally made hydrogels. A range of natural and synthetic polymers are used to design nanocomposite network. By controlling the interactions between nanoparticles and polymer chains, a range of physical, chemical, and biological properties can be engineered. The combination of organic (polymer) and inorganic (clay) structure gives these hydrogels improved physical, chemical, electrical, biological, and swelling/de-swelling properties that cannot be achieved by either material alone. Inspired by flexible biological tissues, researchers incorporate carbon-based, polymeric, ceramic and/or metallic nanomaterials to give these hydrogels superior characteristics like optical properties and stimulus-sensitivity which can potentially be very helpful to medical and mechanical fields.
Boron nitride nanotubes (BNNTs) are a polymorph of boron nitride. They were predicted in 1994 and experimentally discovered in 1995. Structurally they are similar to carbon nanotubes, which are cylinders with sub-micrometer diameters and micrometer lengths, except that carbon atoms are alternately substituted by nitrogen and boron atoms. However, the properties of BN nanotubes are very different: whereas carbon nanotubes can be metallic or semiconducting depending on the rolling direction and radius, a BN nanotube is an electrical insulator with a bandgap of ~5.5 eV, basically independent of tube chirality and morphology. In addition, a layered BN structure is much more thermally and chemically stable than a graphitic carbon structure. BNNTs have unique physical and chemical properties, when compared to Carbon Nanotubes (CNTs) providing a very wide range of commercial and scientific applications. Although BNNTs and CNTs share similar tensile strength properties of circa 100 times stronger than steel and 50 times stronger than industrial-grade carbon fibre, BNNTs can withstand high temperatures of up to 900 °C. as opposed to CNTs which remain stable up to temperatures of 400 °C, and are also capable of absorbing radiation. BNNTS are packed with physicochemical features including high hydrophobicity and considerable hydrogen storage capacity and they are being investigated for possible medical and biomedical applications, including gene delivery, drug delivery, neutron capture therapy, and more generally as biomaterials BNNTs are also superior to CNTs in the way they bond to polymers giving rise to many new applications and composite materials.
In nanotechnology, carbon nanotube interconnects refer to the proposed use of carbon nanotubes in the interconnects between the elements of an integrated circuit. Carbon nanotubes (CNTs) can be thought of as single atomic layer graphite sheets rolled up to form seamless cylinders. Depending on the direction on which they are rolled, CNTs can be semiconducting or metallic. Metallic carbon nanotubes have been identified as a possible interconnect material for the future technology generations and to replace copper interconnects. Electron transport can go over long nanotube lengths, 1 μm, enabling CNTs to carry very high currents (i.e. up to a current density of 109 A∙cm−2) with essentially no heating due to nearly one dimensional electronic structure. Despite the current saturation in CNTs at high fields, the mitigation of such effects is possible due to encapsulated nanowires.
In materials science, a polymer matrix composite (PMC) is a composite material composed of a variety of short or continuous fibers bound together by a matrix of organic polymers. PMCs are designed to transfer loads between fibers of a matrix. Some of the advantages with PMCs include their light weight, high resistance to abrasion and corrosion, and high stiffness and strength along the direction of their reinforcements.
Structural batteries are multifunctional materials or structures, capable of acting as an electrochemical energy storage system while possessing mechanical integrity.
Alan Kin-tak Lau is a Hong Kong engineer and academic. He is the president and chair professor of product innovation at Technological and Higher Education Institute (Thei) of Hong Kong. Prior to this appointment, he was pro vice-chancellor at Swinburne University of Technology. He is also the Independent non-executive director of King’s Flair International (Holdings) Limited, the international vice president and trustee board member of The Institution of Mechanical Engineers (2014-2019) and an academic advisor at Asia University. He was also appointed the chair of professional accreditation panel for APEC/IPEA for Korea. From 2014 to 2016, he was the Alex Wong/Gigi Wong Endowed Professor in Product Engineering Design at the Hong Kong Polytechnic University (HPKU). Currently, he is a Fellow of European Academy of Sciences and Arts, the European Academy of Sciences. Lau has conducted research in the field of mechanical engineering, aerospace engineering and materials engineering. His work has been focused on aerospace composites, unmanned aerial vehicle, product design and engineering and bio-composites. Lau is recognized as Australian National Research Leader in Composite Materials 2019, published by The Australian Post. Within the period 2020-2022, he was director of Oceania Cybersecurity Centre Limited and Stawell Underground Physics Laboratory Company. He has been named as “2023 年度傑出人物” and “2024 年度全球傑出華人領袖”. Currently, he has been appointed as 中氫聚力首席技術官, 莞港創科合作顧問委員會成員 and 力嘉（上海）新能源有限公司首席顧. Dr. Lau also established two academician workstations (院士工作站) with Basalt Fibre Composites Development Company Limited and Hebei University of Technology supported by Sichuan’s and Tianjin’s provincial Governments, respectively to support the conversion of new technologies, like basalt fibre reinforced polymer composites and 3D printed concrete bridges to the industry.
Structural composite supercapacitors are multifunctional materials that can both bear mechanical load and store electrical energy. That when combined with structural batteries, could potentially enable an overall weight reduction of electric vehicles.
Nano-I-beams are nanostructures characterized by their Ɪ-shaped cross-section, resembling the letter Ɪ in macroscopic scale. They are typically made from hybrid organic/inorganic materials and have unique properties that make them suitable for various applications in structural nano-mechanics.
Dimitris C. Lagoudas is a Greek American mechanical engineer, academic, and author. He is a professor of aerospace engineering and materials science and engineering as well as a University Distinguished Professor at Texas A&M University.
References
- ↑ Gibson, Ronald F. (2010). "A review of recent research on mechanics of multifunctional composite materials and structures". Composite Structures. 92 (12). Elsevier BV: 2793–2810. doi:10.1016/j.compstruct.2010.05.003. ISSN 0263-8223.
- ↑ "Sensors and actuators based on carbon nanotubes and their composite" J. Composites Science and Technology 68 (2008) 1227–1249
- ↑ Challenges and opportunities in multifunctional nanocomposite structures for aerospace applications. MRS Bull 2007;32(4):324-34
- ↑ Chaudhary, Birendra; Matos, Helio; Das, Sumanta; Owens, Jim (2023-06-01). "Multifunctional carbon/epoxy composites with power transmission capabilities". Materials Today Communications. 35: 105665. doi: 10.1016/j.mtcomm.2023.105665 . ISSN 2352-4928.
- ↑ O. Kolednik, Functionally Graded Materials, 2008 Archived 2010-08-20 at the Wayback Machine
