High Yield Magnetic Nanoparticles Filled Multiwalled Carbon Nanotubes Using Pulsed Laser Deposition

We present a high yield filling technique of multi-walled carbon nanotubes (MWCNTs), grown vertically on a SiO2 substrate, with magnetic nanoparticles using pulsed laser deposition (PLD). Magnetization measurements in-plane and out-of-plane with respect to the sample surface indicate reasonable coercivity estimated at 0.4 T. The magnetic anisotropy is however found to be randomly oriented, indicating a polycrystalline structure. The unique difference between the in-plane and out-of-plane magnetizations is the sharing produced by the demagnetizing field in the perpendicular direction.

This book gives a survey of the physics and fabrication of carbon nanotubes and their applications in optics, electronics, chemistry and biotechnology. It focuses on the structural characterization of various carbon nanotubes, fabrication of vertically or parallel aligned carbon nanotubes on substrates or in composites, physical properties for their alignment, and applications of aligned carbon nanotubes in field emission, optical antennas, light transmission, solar cells, chemical devices, bio-devices, and many others. Major fabrication methods are illustrated in detail, particularly the most widely used PECVD growth technique on which various device integration schemes are based, followed by applications such as electrical interconnects, nanodiodes, optical antennas, and nanocoax solar cells, whereas current limitations and challenges are also be discussed to lay the foundation for future developments.

Magnetic nano-additives for polymer nanocomposites are achieved using multi-walled carbon nanotubes (MWCNTs) by functionalizing with oxygen plasma and by coating with ferromagnetic nickel (Ni) layers. CNT-polymer nanocomposites are highly sought multi-functional materials for their tailorable properties. If integrated properly, CNT-polymer nanocomposites can deliver improved interlayer mechanical strength and fracture toughness, high electrical conductivity and current carrying capacity, anisotropic thermal management, and smart functions like actuation and sensing. Currently, the most commonly used commercialaerospace structural material, carbon fiber reinforced plastic (CFRP), has high mass-specific mechanical strength, but is prone to delamination due to weak interlaminar strength and require additional heavy, metal mesh layers due to low electrical and thermal conductivities. Thus many studies have been conducted to integrate light-weight CNT-polymer nanocomposites with high performance in order to improve properties of CFRPs. However, bulk application of CNT-polymer nanocomposites is currently limited due to lack of scalablemanufacturing while maintaining organization of CNTs. Dispersion and organization of CNTs are difficult as CNTs tend to agglomerate due van der Waals forces and often entangle due to their high aspect ratios (>~100). These CNT agglomerates in polymer matrices cause voids and behave as defects rather than reinforcement, resulting in property degradation. Interfaces and interphases formed between CNTs and polymer matrices also need to be tuned to avoid functioning as defects or boundary layers. Thus, it is critical to develop a method to effectively disperse and organize CNTs within polymer matrices to improve and tailor the nanocomposite's multi-functional properties. Here, application of magnetic fields is a promising, scalable method to deliver bulk amount of nanocomposites while maintaining organized nanoparticle assemblythroughout the polymer matrix before the curing step. Previous studies showed effective alignment of nanoparticles with the small magnetic field (~10 G, an order of magnitude above the earth's natural magnetic field) for reasonable time (~1 hour). In addition, nanoparticle alignment spacing was successfully controlled by varying field oscillation frequency, enabling particle patterning and interface tuning. In this work, MWCNTs (~35 nm diameter and ~200 um length) were processed to be magnetic, so that they can function as additives that can be effectively organized with magnetic fields. MWCNTs, being diamagnetic as fabricated, are coated with a thin layer of Ni with high aspect ratio to exhibit anisotropic ferromagnetism. The process consisted of three steps. First, MWCNTs were synthesized with chemical vapor deposition (CVD). Second, these MWCNTs were treated with low temperature air plasma; the amorphous carbon present on the side walls and entangled CNT layers on the top surface were eliminated. The CNT surfaces were also functionalized, in order to increase adhesion with Ni coating and to improve dispersion and suspension within matrix solutions. The air plasma conditions (power and treatment time) were varied to ensure adequate cleaning, and to maximize functionalization of CNTs without overly damaging the CNT crystal structure. Treated CNTs and their dispersion degree were inspected visually with scanning electron microscopy (SEM), and functional group attachment was quantitatively evaluated using X-ray photoelectron spectroscopy (XPS). From these preliminary results, better CNT dispersion and suspension in isopropyl alcohol (IPA) was observed with the plasma treatment with low (~6.8 W) power setting for moderate duration (~4 min), which can be attributed to most attachment of ether (C-O) functional groups. Third, thin Ni layers, with varying thickness from 20 nm to 100 nm, were e-beam evaporated on the functionalized CNTs. Anisotropic ferromagnetic properties,such as hysteresis, coercivity, and remanence were measured using a vibrating sample magnetometer (VSM). With increasing thickness, magnetization increased but magnetic anisotropy decreased. Finally, preliminary study confirmed effective magnetic alignment of MWCNTs with ~100 nm thick Ni coating dispersed in IPA when applied with weak magnetic fields of ~100 G for 15 min.

Giant Moment Enhancement of Magnetic Nanoparticles Embedded in Multi-Walled Carbon Nanotubes: Consistent with Ultrahigh Temperature Superconductivity.

Handbook containing more than 100 of the most common experimental procedures in nanoscience.

This book covers topics related to drug delivery, biomaterials, drug design, formulation development, nanoscience, and nanotechnology. It describes the fundamental concepts in nanotechnology and their different applications in biotechnology to solve engineering challenges and generate new areas of technological development. Nanobiotechnology: Applications of Nanomaterials in Biotechnology, Medicine, and Healthcare covers vast application areas that include medical science, material science, pharmaceutical science, and environmental science. Section 1 presents recent research updates on the different nanomaterials, which are promising in different medical and biotechnological applications. Applications of nanomaterials as bone replacement orthopedic implants have revolutionized the treatment of orthopedic surgery. Nanostructured polymeric materials have gained immense research attention as therapeutic carriers for the precise delivery of drugs at targeted sites. Nanocellulose is recognized as a promising green nanomaterial due to its renewability and abundance in nature. Scientific topics on the most recent scientific and technological advances and applications of different nanostructured materials are presented in this section. Section 2 focuses on the novel synthesis methods that are used extensively and are promising for large-scale production of inorganic and nanostructured materials. Section 3 covers the applications of nanotools in the treatment of different diseases, including cancers and genetic diseases. The increasing use of nanotechnology will bring changes in the manufacturing processes of nanomaterials. The applications of nanomaterials in the field of medical imaging and molecular detection are presented in section 4. This book will be useful for students, researchers, scientists, academicians, and industrial manufacturers to understand the importance and applicability of nanomaterials in the field of biotechnology and medical science.

This book explores the potential of multi-functional carbon nanotubes for biomedical applications. It combines contributions from chemistry, physics, biology, engineering, and medicine. The complete overview of the state-of-the-art addresses different synthesis and biofunctionalisation routes and shows the structural and magnetic properties of nanotubes relevant to biomedical applications. Particular emphasis is put on the interaction of carbon nanotubes with biological environments, i.e. toxicity, biocompatibility, cellular uptake, intracellular distribution, interaction with the immune system and environmental impact. The insertion of NMR-active substances allows diagnostic usage as markers and sensors, e.g. for imaging and contactless local temperature sensing. The potential of nanotubes for therapeutic applications is highlighted by studies on chemotherapeutic drug filling and release, targeting and magnetic hyperthermia studies for anti-cancer treatment at the cellular level.

A crucial overview of the cutting-edge in nanocarbon research and applications In Synthesis and Applications of Nanocarbons, the distinguished authors have set out to discuss fundamental topics, synthetic approaches, materials challenges, and various applications of this rapidly developing technology. Nanocarbons have recently emerged as a promising material for chemical, energy, environmental, and medical applications because of their unique chemical properties and their rich surface chemistries. This book is the latest entry in the Wiley book series Nanocarbon Chemistry and Interfaces and seeks to comprehensively address many of the newly surfacing areas of controversy and development in the field. This book introduces foundational concepts in nanocarbon technology, hybrids, and applications, while also covering the most recent and cutting-edge developments in this area of study. Synthesis and Applications of Nanocarbons addresses new discoveries in the field, including: · Nanodiamonds · Onion-like carbons · Carbon nanotubes · Fullerenes · Carbon dots · Carbon fibers · Graphene · Aerographite This book provides a transversal view of the various nanocarbon materials and hybrids and helps to share knowledge between the communities of each material and hybrid type.