Ion Beam Techniques and Applications

A wide variety of ion beam techniques are being used in several versatile applications ranging from environmental science, nuclear physics, microdevice fabrication to materials science. In addition, new applications of ion beam techniques across a broad range of disciplines and fields are also being discovered frequently. In this book, the latest research and development on progress in ion beam techniques has been compiled and an overview of ion beam irradiation-induced applications in nanomaterial-focused ion beam applications, ion beam analysis techniques, as well as ion implantation application in cells is provided. Moreover, simulations of ion beam-induced damage to structural materials of nuclear fusion reactors are also presented in this book

Reaction between Energy Particle Ion Beam with Carbon Nanotube

Carbon nanotubes (CNTs) have attracted considerable attention due to their high aspect ratio, whisker-like form for best possible geometrical field enhancement, high electrical conductivity, and extraordinary thermal stability. Ion beam technology is a potential technique for controlled construction of CNTs. During collision with energetic ions, carbon atom of CNTs can get an adequate amount of energy to escape from the graphite lattice and produce a large number of defects. These defects are advantageous for adding some new functional groups and nanoparticles to modify CNTs. Meanwhile, the structure and atoms in the region of the defects can be rearranged and changed into amorphous structure, onion structure, and so on. These defects also can be used to form the junctions of CNTs and realize welding of CNTs and network formation of amorphous carbon nanowires

Toward Ultralight High Strength Structural Materials via Collapsed Carbon Nanotube Bonding

The growing commercial availability of carbon nanotube (CNT) macro-assemblies such as sheet and yarn is making their use in structural composite components increasingly feasible. However, the mechanical properties of these materials continue to trail those of state-of-the-art carbon fiber composites due to relatively weak inter-tube load transfer. Forming covalent links between adjacent CNTs promises to mitigate this problem, but it has proven difficult in practice to introduce them chemically within densified and aligned CNT materials due to their low permeability. To avoid this limitation, this work explores the combination of pulsed electrical current, temperature, and pressure to introduce inter-CNT bonds. Reactive molecular dynamics simulations identify the most probable locations, configurations, and conditions for inter-nanotube bonds to form. This process is shown to introduce covalent linkages within the CNT material that manifest as improved macroscale mechanical properties. The magnitude of this effect increases with increasing levels of prealignment of the CNT material, promising a new synthesis pathway to ultralight structural materials with specific strengths and stiffnesses exceeding 1 and 100 GPa/(g/cu.cm), respectively

Material incorporation inside single-walled carbon nanotubes using plasma-ion irradiation method

科研費報告書収録論文(課題番号:13852016/研究代表者:畠山力三/プラズマイオン照射による新機能性進化ナノチューブ創製法の開発

The fabrication and application of carbon nanotube-based hybrid nanomaterials

The evolution of technology has reached a stage where the performances and dimension needed are outpacing what conventional materials can deliver. This has been made more acute with the further necessity of miniaturisation. Therefore, new materials which can overcome this bottleneck are required. Over the past few decades, it was found that when a material is reduced to the nanoscale, they can exhibit properties unparallel by their bulk counterparts. Therefore these nanomaterials poise as a promising candidate for future applications. Of the many nanomaterials, carbon nanotube (CNT) is among the most emblematic. CNT is a hollow one-dimensional structure comprising solely of carbon atoms. They are fascinating as they exhibit physical attributes which surpass many conventional materials and their nanoscale dimension allows greater flexibility in their deployments. However, the utilisation of CNTs is currently frustrated by a host of intrinsic and extrinsic factors. As a result, there are usually significant disparity between their predicted capability and real-world performance. Therefore, the practical application of CNTs remains unfeasible. The premise of this thesis is that by employing CNTs in conjunction with other materials, the hurdles which plague their utilisation may be overcome. Here, the concept of CNT-based hybrid nanomaterials is presented. This thesis demonstrates that by engineering complementary interaction between two materials, many challenges which hamper the utilisations of CNTs and other nanomaterials can indeed be negated. Furthermore, their synergistic interaction allows the performance of the CNT-based hybrid nanomaterials to be superior to their uncoupled precursors. Therefore, this could be a viable strategy to incorporating nanomaterials in a range of applications

Ultra high molecular weight polyethylene and its reinforcement with Carbon Nanotubes in Medical Devices

This chapter discusses the advantages and complexities of ultra high molecular weight polyethylene(UHMWPE) when used as a bearing material for total joint arthroplasty (TJA) and total knee arthroplasty(TKA). The UHMWPE internal structure and its mechanical response depend strongly on a diversity offactors that include radiation crosslinking, fiber reinforcement, and the addition of antioxidants such asVitamin E or Vitamin C. All these manufacturing procedures induce morphological changes andsimultaneously alter the mechanical properties of UHMWPE. The importance of UHMWPE on arthroplasty,including the advantages, the limitations and the strategies devised to overcome the knowndrawbacks are discussed in the first section. The following sections revise and discuss thebiocompatibility, the manufacturing processes, the tribological behaviour, the aging by oxidation andirradiation of UHMWPE and UHMWPE-CNT nanocomposites. The last section analyses the viscoelasticbehavior of UHMWPE and its implications on the long-term survival of total joint arthroplasty

Femtosecond laser studies of fullerenes and nanotubes

This work concerns the interaction of intense, ultrashort laser pulses with fullerenes and carbon nanotubes. This includes the excitation and ionisation dynamics of gas phase fullerenes and the response of carbon nanotubes to intense ultrashort laser pulses. When ionising C60 with laser pulses of duration between 50 fs up to a few hundred fs, the ionisation mechanism has been proposed to be thermal in nature, with the electronic subsystem ‘hot’ and the vibrational system ‘cold’ at the time of ionisation. Recent results show an anisotropy in the photoelectron angular distribution which may suggest more direct mechanisms at work. Velocity-Map Imaging photoelectron spectroscopy results are presented for the ionisation of C60 and C70 at various wavelengths, pulse durations and intensities and the results are compared to theoretical models. The results are described well by a thermal ionisation mechanism in which a significant number of electrons are emitted during the laser pulse. Electrons may gain a momentum ‘kick’ from the electric field of the laser which results in an anisotropy in the photoelectron angular distributions. Peaks are observed, superimposed on the thermal background, in the photoelectron kinetic energy spectra of fullerenes ionised by ultrashort laser pulses which were previously assigned as Rydberg peaks. Photoelectron angular distributions of these peaks are presented for C60 and C70 ionised with laser pulses of various wavelengths. The binding energies and anisotropy parameters fitted to the peaks suggest that they are due to the population and one-photon ionisation of superatom molecular orbitals (SAMOs). The results rule out a direct multiphoton population mechanism for these states and show many similarities with Rydberg fingerprint spectroscopy. The fusion of carbon nanotubes has been observed under high energy electron beams and fullerene molecules have been shown to fuse together after irradiation with ultrashort laser pulses. Results are presented for experiments where fusion of carbon nanotubes with ultrashort laser pulses was attempted. Thin carbon nanotube films are analysed via Raman spectroscopy after irradiation by single laser pulses. A number of low frequency radial breathing mode peaks were observed which suggest that fusion may have taken place at certain areas of the sample