Download or read book Thermal and Mechanical Phenomena in Aligned Carbon Nanotube Films written by Yuan Gao and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Efficient heat conduction is critical to the performance and reliability of a variety of devices. To ensure efficient heat removal from electronic devices, thermal interface materials (TIMs) are used to enhance heat conduction between two contacting surfaces. Ideal TIMs have high thermal conductivity, conform to the microscale roughness of the surfaces in contact, and accommodate stresses due to mismatch in thermal expansion coefficients. Commercial TIMs exhibit a tradeoff between these desired thermal and mechanical properties. Vertically aligned carbon nanotube (VACNT) films have great promise as TIMs because they have high through-plane thermal conductance and mechanical compliance. VACNT films are typically composed of a complex, entangled network of CNTs and the density and alignment of CNTs within a film affect its mechanical and thermal properties. Given the variety of growth techniques and variations in film morphology, it is important to understand how these factors influence film behavior. The present work combines three major aspects of VACNT film characterization: mechanical and thermal characterization, analysis of the film microstructure, and modeling of the film properties. The inhomogeneous VACNT film morphology is investigated by using image analysis to quantify CNT alignment and density and by measuring the elastic modulus at the top and bottom film surfaces using nanoindentation. The alignment and density information is input into a model of the mechanical response of the VACNT film, which is compared to measured data. The through-plane thermal properties of VACNT films are measured using thermoreflectance techniques. Multiwall VACNT films are grown directly on a thermoelectric material and the thermal properties of the films are characterized using nanosecond thermoreflectance. A set of eight single-wall VACNT films are measured using frequency domain thermoreflectance to extract four relevant thermal properties: thermal conductivity, heat capacity, and the upper and lower boundary resistances.
Download or read book Wafer scale Alignment of Semiconducting Carbon Nanotubes from Solution written by Katherine Rose Jinkins and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon nanotubes are unique one-dimensional materials that exhibit extraordinary properties, including high stability, large elastic modulus, and exceptional charge and thermal transport, making them promising candidates for future mechanical, optical, and electronic devices. Electrical measurements of individual nanotubes have demonstrated room-temperature ballistic conductance and 3× higher current density than state-of-the-art Si field-effect transistors (FETs). While these results are exciting; to achieve the high on-current required for future carbon nanotube technologies to become viable, electronic devices must incorporate multiple nanotubes aligned in parallel. Alignment is especially critical to minimize sheet resistance and reduce charge carrier scattering in devices. However, the alignment of carbon nanotubes at intermediate packing densities in a scalable technique has plagued the electronics community for decades. In this work, we develop, explore, and elucidate three possible solutions to this long-standing challenge. First, we elucidate the mechanism of the floating evaporative self-assembly (FESA) technique, in which stripes of aligned nanotubes are deposited onto substrates by dosing a carbon nanotube ink at a water/substrate interface. We track the key interfaces directly at the substrate during FESA and show that the nanotube alignment occurs from the buried ink/water interface. We also demonstrate improved control over the bandwidth and band spacing of aligned carbon nanotubes and align nanotubes across a 2.5 × 2.5 cm2 substrate, an important step towards high-volume production. Ultimately, though, FESA cannot yield uniform, continuous films of aligned nanotubes over the wafer-scale, so other techniques are explored. We use the understanding gained toward the FESA mechanism to develop another alignment technique, tangential flow interfacial self-assembly (TaFISA), to fabricate uniform films of highly aligned carbon nanotubes for short channel FETs. In this process, we demonstrate that an ink/water interface can induce liquid crystal assembly of carbon nanotubes. Flowing this two-dimensional nematic assembly of nanotubes, globally aligns the nanotubes. By translating a substrate through this flowing ink/water interface, uniform films of highly aligned (within ±5.7°) nanotubes are deposited across 10 cm wide substrates. Due to the underlying lyotropic liquid crystal phenomena, the nanotube ordering improves with increasing concentration and decreasing temperature. The exceptional alignment leads to excellent FET performance with high on-state current density averaging 520 [mu]A [mu]m−1 at a V[DS] of -0.6 V. We also perform a more detailed investigation of experimental parameters that can affect the interfacial assembly, including nanotube ink solvent, substrate surface water contact angle, and modification of the water subphase. We also study the effect of shear on nanotube ink, without the ink/water interface as used in the FESA and TaFISA technique. We elucidate the effect of shear rate on nanotube alignment and find that the alignment increases with increasing shear rate following a power law dependence. We also demonstrate control over the nanotube packing density by tailoring the carbon nanotube ink concentration and ink volume. FETs are fabricated with their charge transport direction parallel and perpendicular to the alignment. The parallel FETs exhibit 7× faster charge carrier mobility of 101 cm2 V−1 s−1, while also simultaneously displaying high on/off ratio of 105. Deposition conditions are extensively optimized to enable alignment within a ± 27° window at nearly ideal packing density of 50 nanotubes [mu]m−1 over large-area 10 × 10 cm2 substrates. These quasi-aligned films are promising candidates for long-channel FETs (e.g., in displays, sensors, and flexible electronics), where some misalignment is necessary to allow charge percolation. We additionally report our work utilizing solution-based shear to fabricate ultrathin films of aligned cellulose nanocrystals. Cellulose nanocrystals (CNC) exhibit excellent mechanical and piezoelectric properties, making this material attractive for use in high-performance coatings. Toward this goal, we use confined shear-based alignment to fabricate ultrathin films of aligned CNC. The shear rate is varied from 19 to 19000 s−1 to improve the half-width at half-maximum of the spread in CNC alignment from 130 to 30°. The CNC solution volume and concentration are both used to independently control the film height.
Download or read book Carbon Nanotube Films and Microjet Cooling Devices for Thermal Management written by Yoon Jin Won and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The downsizing of electronic devices and the consequent increasing power densities pose thermal management challenges for the semiconductor industry. Since the present thermal solutions limit their cooling capacity, developing new cooling methods for electronic devices has become important. This dissertation presents two types of novel methods for heat dissipation from integrated circuits: One is the use of advanced thermal interface materials, such as carbon nanotubes (CNTs), to increase heat dissipation between the solid and solid surface, such as a chip and heat sink. The second method is the use of a microjet impingement device to improve heat transfer between a liquid and solid in a heat sink. As advanced interface materials, vertically aligned carbon nanotube films are promising because of their unique mechanical and thermal properties. The first part of the dissertation describes the design, fabrication, and testing of CNTs using resonators to characterize their mechanical properties. Discussed in detail is the preparation of carbon nanotubes using different recipes, resulting in varied thicknesses of single-walled carbon nanotube films and multi-walled carbon nanotube films. The measurements of the resonant frequency shifts due to the presence of the CNT films using a laser Doppler vibrometer system result in extracted moduli of 0.5-220 [Mu]m-thick nanotube films varying from 1 to 370 MPa. To show how the physics between the effective modulus and thickness are connected, an analysis for the height dependence of the modulus is provided. After an image analysis is presented, a nanotube dynamics simulation based on tube properties and film morphology is introduced to predict mechanical properties. In addition to discussing the proposed interface materials, the second part of the dissertation describes the design, fabrication and testing of microjet impingement cooling, which display high heat capacities, as an advanced thermal management solution. The design of single-jet and multi-jet arrays with different numbers of diameters, locations, and spacing is discussed. Specifically, this part demonstrates how the microjet hydrodynamics are quantified using two-dimensional images by [Mu]PIV techniques, enabling the reconstruction of the three-dimensional flow field. The results indicate that CNT films offer a mechanical compliance that is suitable for TIM applications and that the microscale liquid jet devices provide quantified flow physics for heat sink applications.
Download or read book Carbon Nanotubes written by Mohamed Berber and published by BoD – Books on Demand. This book was released on 2016-07-20 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book shows the recent advances of the applications of carbon nanotubes (CNTs), in particular, the polymer functionalized carbon nanotubes. It also includes a comprehensive description of carbon nanotubes' preparation, properties, and characterization. Therefore, we have attempted to provide detailed information about the polymer-carbon nanotube composites. With regard to the unique structure and properties of carbon nanotubes, a series of important findings have been reported. The unique properties of carbon nanotubes, including thermal, mechanical, and electrical properties, after polymer functionalization have been documented in detail. This book comprises 18 chapters. The chapters include different applications of polymer functionalization CNTs, e.g. photovoltaic, biomedical, drug delivery, gene delivery, stem cell therapy, thermal therapy, biological detection and imaging, electroanalytical, energy, supercapacitor, and gas sensor applications.
Download or read book Carbon Nanotube Polymer Composites written by Dimitrios Tasis and published by Royal Society of Chemistry. This book was released on 2015-11-09 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemically-modified carbon nanotubes (CNTs) exhibit a wide range of physical and chemical properties which makes them an attractive starting material for the preparation of super-strong and highly-conductive fibres and films. Much information is available across the primary literature, making it difficult to obtain an overall picture of the state-of-the-art. This volume brings together some of the leading researchers in the field from across the globe to present the potential these materials have, not only in developing and characterising novel materials but also the devices which can be fabricated from them. Topics featured in the book include Raman characterisation, industrial polymer materials, actuators and sensors and polymer reinforcement, with chapters prepared by highly-cited authors from across the globe. A valuable handbook for any academic or industrial laboratory, this book will appeal to newcomers to the field and established researchers alike.
Download or read book Carbon Nanotubes written by Mohammed Rahman and published by BoD – Books on Demand. This book was released on 2018-04-26 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book Carbon Nanotubes - Recent Progress contains a number of recent researches on synthesis, growth, characterization, development, and potential applications on carbon materials especially CNTs in nanoscale. It is a promising novel research from top to bottom that has received a lot of interest in the last few decades. It covers the advanced topics on the physical, chemical, and potential applications of CNTs. Here, the interesting reports on cutting-edge science and technology related to synthesis, morphology, control, hybridization, and prospective applications of CNTs are concluded. This potentially unique work offers various approaches on the R
Download or read book Effects of Temperature on Electrical Resistance in Aligned Carbon Nanotube Films written by Eric A. Lass and published by . This book was released on 2003 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Society for Composites written by Michael Hyer and published by DEStech Publications, Inc. This book was released on 2011-06-28 with total page 2760 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nanocomposites written by Tsu-Wei Chou and published by DEStech Publications, Inc. This book was released on 2012 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: A bound edition that contains research papers on using nanomaterials to improve the performance and properties of composites. It covers all phases of nanocomposite synthesis - from design and multiscale modeling to processing and testing. It also offers data on dispersion, alignment and interfacial bonding.
Download or read book Carbon Nanotube Based Nanocomposites written by Anna Boczkowska and published by Mdpi AG. This book was released on 2021-10-18 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Special issue, "Carbon nanotube-based nanocomposites", provides an extensive overview of current trends in the area of polymer matrix nanocomposites based on carbon nanotubes (CNTs) from the papers contributed by internationally recognized specialists. The Special Issue brings together 7 papers that deal with the various aspects of processing, as well as experimental and analytical approaches to carbon nanotube-based nanocomposites fabrication, characterization and application. Each paper demonstrates how enhancements in materials, processes and characterization techniques can improve performance in the field of engineering. The Special issue gives a unique opportunity to discover the latest research on carbon nanotube-based nanocomposites from different laboratories. Numerous references are given at the end of each paper to enable the reader to explore the topics covered in greater detail. Most of the papers describe the improvement of electrical and mechanical properties of polymer-based nanocomposites due to the application of CNTs, independently on the matrix used: (ethylene vinyl acetate) copolymer, hot melt copolyamides, epoxy and silicone resins. In each case, the relationships between the processing parameters and microstructure of obtained nanocomposites were described. The synergistic effect of hybrid nanofillers was also explored in nanocomposites with carbon and halloysite nanotubes. The effect of carbon nanotubes on the wear behavior of nanocomposites based on epoxy resin was investigated as well. The original results on the synthesis and characterization of composite shear thickening fluids containing carbon nanofillers are presented. The addition of the CNTs modified the impact absorption ability of such fluids. The presented Special Issue results also proved that CNTs can be used to obtain more resistant and durable cement-based composites.
Download or read book Nanoscale Phenomena written by Zikang Tang and published by Springer Science & Business Media. This book was released on 2007-11-22 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book collects selected lectures from the Third Workshop of the Croucher Advanced Study Institute on Nano Science and Technology, and showcases contributions from world-renowned researchers. The book presents in-depth articles on the latest developments in nanomaterials and nanotechnology, and provides a cross-disciplinary perspective covering physics and biophysics, chemistry, materials science, and engineering.
Download or read book Materials for Advanced Packaging written by Daniel Lu and published by Springer. This book was released on 2016-11-18 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt: Significant progress has been made in advanced packaging in recent years. Several new packaging techniques have been developed and new packaging materials have been introduced. This book provides a comprehensive overview of the recent developments in this industry, particularly in the areas of microelectronics, optoelectronics, digital health, and bio-medical applications. The book discusses established techniques, as well as emerging technologies, in order to provide readers with the most up-to-date developments in advanced packaging.
Download or read book Carbon Nanotubes written by Mildred S. Dresselhaus and published by Springer Science & Business Media. This book was released on 2003-07-01 with total page 461 pages. Available in PDF, EPUB and Kindle. Book excerpt: After a short introduction and a brief review of the relation between carbon nanotubes, graphite and other forms of carbon, the synthesis techniques and growth mechanisms for carbon nanotubes are described. This is followed by reviews on nanotube electronic structure, electrical, optical, and mechanical properties, nanotube imaging and spectroscopy, and nanotube applications.
Download or read book Nanotube Superfiber Materials written by Mark Schulz and published by William Andrew. This book was released on 2019-03-12 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanotube Superfiber Materials: Science, Manufacturing, Commercialization, Second Edition, helps engineers and entrepreneurs understand the science behind the unique properties of nanotube fiber materials, how to efficiency and safely produce them, and how to transition them into commercial products. Each chapter gives an account of the basic science, manufacturing, properties and commercial potential of a specific nanotube material form and its application. New discoveries and technologies are explained, along with experiences in handing-off the improved materials to industry. This book spans nano-science, nano-manufacturing, and the commercialization of nanotube superfiber materials. As such, it opens up the vast commercial potential of nanotube superfiber materials. Applications for nanotube superfiber materials cut across most of the fields of engineering, including spacecraft, automobiles, drones, hyperloop tracks, water and air filters, infrastructure, wind energy, composites, and medicine where nanotube materials enable development of tiny machines that can work inside our bodies to diagnose and treat disease. - Provides up to date information on the applications of nanotube fiber materials - Explores both the manufacturing and commercialization of nanotube superfibers - Sets out the processes for producing macro-scale materials from carbon nanotubes - Describes the unique properties of these materials
Download or read book Carbon Nanotubes written by Michael J. O’Connell and published by CRC Press. This book was released on 2018-10-03 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since their discovery more than a decade ago, carbon nanotubes (CNTs) have held scientists and engineers in captive fascination, seated on the verge of enormous breakthroughs in areas such as medicine, electronics, and materials science, to name but a few. Taking a broad look at CNTs and the tools used to study them, Carbon Nanotubes: Properties and Applications comprises the efforts of leading nanotube researchers led by Michael O’Connell, protégé of the late father of nanotechnology, Richard Smalley. Each chapter is a self-contained treatise on various aspects of CNT synthesis, characterization, modification, and applications. The book opens with a general introduction to the basic characteristics and the history of CNTs, followed by discussions on synthesis methods and the growth of “peapod” structures. Coverage then moves to electronic properties and band structures of single-wall nanotubes (SWNTs), magnetic properties, Raman spectroscopy of electronic and chemical behavior, and electromechanical properties and applications in NEMS (nanoelectromechanical systems). Turning to applications, the final sections of the book explore mechanical properties of SWNTs spun into fibers, sidewall functionalization in composites, and using SWNTs as tips for scanning probe microscopes. Taking a fresh look at this burgeoning field, Carbon Nanotubes: Properties and Applications points the way toward making CNTs commercially viable.
Download or read book Fundamentals of Conjugated Polymer Blends Copolymers and Composites written by Parveen Saini and published by John Wiley & Sons. This book was released on 2015-04-30 with total page 684 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since their discovery in 1977, the evolution of conducting polymers has revolutionized modern science and technology. These polymers enjoy a special status in the area of materials science yet they are not as popular among young readers or common people when compared to other materials like metals, paper, plastics, rubber, textiles, ceramics and composites like concrete. Most importantly, much of the available literature in the form of papers, specific review articles and books is targeted either at advanced readers (scientists / technologists / engineers / senior academicians) or for those who are already familiar with the topic (doctoral / postdoctoral scholars). For a beginner or even school / college students, such compilations are bit difficult to access / digest. In fact, they need proper introduction to the topic of conducting polymers including their discovery, preparation, properties, applications and societal impact, using suitable examples and already known principles/knowledge/phenomenon. Further, active participation of readers in terms of "question & answers", "fill-in-the-blanks", "numerical" along with suitable answer key is necessary to maintain the interest and to initiate the "thought process". The readers also need to know about the drawbacks and any hazards of such materials. Therefore, I believe that a comprehensive source on the science / technology of conducting polymers which maintains a link between grass root fundamentals and state-of-the-art R&D is still missing from the open literature.
Download or read book Carbon Nanotubes written by Siva Yellampalli and published by IntechOpen. This book was released on 2011-07-20 with total page 530 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon nanotubes are one of the most intriguing new materials with extraordinary properties being discovered in the last decade. The unique structure of carbon nanotubes provides nanotubes with extraordinary mechanical and electrical properties. The outstanding properties that these materials possess have opened new interesting researches areas in nanoscience and nanotechnology. Although nanotubes are very promising in a wide variety of fields, application of individual nanotubes for large scale production has been limited. The main roadblocks, which hinder its use, are limited understanding of its synthesis and electrical properties which lead to difficulty in structure control, existence of impurities, and poor processability. This book makes an attempt to provide indepth study and analysis of various synthesis methods, processing techniques and characterization of carbon nanotubes that will lead to the increased applications of carbon nanotubes.
