Author: Publisher:
ISBN: 9789178956685
Category :
Languages : en
Pages :
Book Description
Magnetic-field-directed Self-assembly of Multifunctional Aerosol Nanoparticles
Author: Magnetic Field-Directed Self-Assembly of Magnetic Nanoparticle Chains in Polymers
Author: Peter John KrommenhoekPublisher:
ISBN:
Category :
Languages : en
Pages : 133
Book Description
Magnetic Nanoparticle Field Directed Self-assembly
Author: Ryan Michael SchmidtPublisher:
ISBN:
Category : Block copolymers
Languages : en
Pages : 153
Book Description
Directed self-assembly of nanomaterials via external fields is an attractive processing tool for industry as it is inherently inexpensive and flexible. The self-assembly of magnetic nanoparticles in particular has gained much recent interest for applications ranging from biomedical imaging and targeted cancer therapy to ferrofluid mechanical damping devices, that rely on the state of aggregation and alignment of the nanoparticles. We utilize an oil-water platform to directly observe directed self-assembly of magnetic nanoparticles that are field ordered into two-dimensional mesostructures through the fossilized liquid assembly method. Our system consisted of polymer-coated iron-oxide nanoparticles which were assembled at the interface between a crosslinkable hydrophobic monomer oil, and water through the use of external magnetic fields, and then cured with UV light. In this study, entire magnetic flux field lines in various geometrical configurations were successfully modeled and mapped out by the magnetic nanoparticles, both in-plane and in perpendicular orientations utilizing FLA. As the microscopic behavior of magnetic nanoparticles is known through this first study, further work can then be conducted through the assembly of block copolymer/magnetic nanoparticle nanocomposites. The morphology of neat self-assembled block copolymers have been extensively studied and it has been proven that the molecular weight, volume fraction of the components, and the degree of segment incompatibility are the three independent parameters used to determine equilibrium morphologies. The assembled orientations of lamellar and cylindrical morphologies in particular develop specific directionalities depending on the natural interactions of the blocks with the substrate and surface. It has been shown that treatments such as UV-Ozone treatment of the substrate, mechanical shear, or electrical fields can force this directionality to be altered, however few methods have been developed to readily alter preferential morphologies through the use of magnetic fields. In order to provide preliminary results toward the validity of a magnetically driven reorientation process, systems of polystyrene-b-poly(methylmethacrylate) with varying molecular weights were loaded with up to 1% polystyrene coated cobalt nanoparticles. This study successfully showed that the particles can be loaded into the block copolymers without disrupting the morphology of the block copolymers, and also provided initial results that this method is plausible.
Plasma Synthesis and Self-Assembly of Magnetic Nanoparticles
Author: Sebastian EkerothPublisher: Linköping University Electronic Press
ISBN: 9176850099
Category :
Languages : en
Pages : 58
Book Description
Nanomaterials are important tools for enabling technological progress as they can provide dramatically different properties as compared to the bulk counterparts. The field of nanoparticles is one of the most investigated within nanomaterials, thanks to the existing, relatively simple, means of manufacturing. In this thesis, high-power pulsed hollow cathode sputtering is used to nucleate and grow magnetic nanoparticles in a plasma. This sputtering technique provides a high degree of ionization of the sputtered material, which has previously been shown to aid in the growth of the nanoparticles. The magnetic properties of the particles are utilized and makes it possible for the grown particles to act as building blocks for self-assembly into more sophisticated nano structures, particularly when an external magnetic field is applied. These structures created are termed “nanowires” or “nanotrusses”, depending on the level of branching and inter-linking that occurs. Several different elements have been investigated in this thesis. In a novel approach, it is shown how nanoparticles with more advanced structures, and containing material from two hollow cathodes, can be fabricated using high-power pulses. The dual-element particles are achieved by using two distinct and individual elemental cathodes, and a pulse process that allows tuning of individual pulses separately to them. Nanoparticles grown and investigated are Fe, Ni, Pt, Fe-Ni and Ni-Pt. Alternatively, the addition of oxygen to the process allows the formation of oxide or hybrid metal oxide – metal particles. For all nanoparticles containing several elements, it is demonstrated that the stoichiometry can be easily varied, either by the amount of reactive gas let into the process or by tuning the amount of sputtered material through adjusting the electric power supplied to the different cathodes. One aim of the presented work is to find a suitable material for the use as a catalyst in the production of H2 gas through the process of water splitting. H2 is a good candidate to replace fossil fuels as an energy carrier. However, rare elements (such as Ir or Pt) needs to be used as the catalyst, otherwise a high overpotential is required for the splitting to occur, leading to a low efficiency. This work demonstrates a possible route to avoid this, by using nanomaterials to increase the surface-to-volume ratio, as well as optimizing the elemental ratio between different materials to lower the amount of noble elements required.
Self-assembly of Nanoparticles Under External Magnetic Field
Author: Xiaowei TengPublisher:
ISBN:
Category : Chemical engineering
Languages : en
Pages :
Book Description
Multifunctional Plasmonic and Magnetic Nanostructures Guided by Self and Directed Assembly
Author: Muzahidul Islam AnikPublisher:
ISBN:
Category : Chemical engineering
Languages : en
Pages : 0
Book Description
Directed Self-assembly of Nanoparticles
Author: Benjamin L. FrankampPublisher:
ISBN:
Category : Nanoparticles
Languages : en
Pages : 388
Book Description
Directed Self-assembly of Nanoparticles at Interfaces
Author: Yao LinPublisher:
ISBN:
Category : Liquid-liquid interfaces
Languages : en
Pages : 182
Book Description
Electric Field Directed Self Assembly of Nanoparticle Structures
Author: Dietrich Alexander DehlingerPublisher:
ISBN:
Category :
Languages : en
Pages : 180
Book Description
It is traditionally difficult to integrate a wide range of nanocomponents into macroscopic or mesoscopic scale systems. Traditional methods of nanofabrication use large scale patterning of homogenous layers, or make use of the intrinsic properties of the particles in to bind them together in an uncontrolled fashion. In this dissertation, a method for the rapid, highly controlled deposition of water soluble nanoparticles is demonstrated. Through the use of direct current controlled electrodes in a buffered solution, nanoparticles are pulled from a dilute solution to a complementary binding surface in a few seconds where they form a single layer. By repeated processing steps we are able to rapidly fabricate multilayered structures using different nanoparticles, making use of both overall directed assembly and the local self assembly of the particles themselves. Because we are able to control the particle concentration, we can effectively control the particle binding rate at the deposition surface. Described in detail is a method for characterizing the deposition process to determine both the optimal parameters (in terms of deposition time and current) for a given particle type, and methods to determine the level of interparticle self binding. Optical fluorescent imaging and electron microscopy were used extensively to characterize the rate of particle accumulation both as a function of current and time for a single deposition, and for the overall process through subsequent layers. The electric field assisted self assembly work was carried out for 40nm and 200nm biotin/streptavidin coated particles, as well as particles covered in various DNA sequences, quantum dots, and gold particles. Particle deposition profiles across the electrode are also discussed, with the root causes for the observed pattern explained using various electric field deposition from this work, as well as some supporting experiments from tangentially related experiments. These experimental results are compared to various simulated systems. Finally some preliminary work on long range, high voltage, high conductivity dielectrophoresis systems is discussed with an eye towards fully integrated sample analysis systems.
Self-Assembled Nanostructures
Author: Jin ZhangPublisher: Springer Science & Business Media
ISBN: 0306479419
Category : Science
Languages : en
Pages : 327
Book Description
Nanostructures refer to materials that have relevant dimensions on the nanometer length scales and reside in the mesoscopic regime between isolated atoms and molecules in bulk matter. These materials have unique physical properties that are distinctly different from bulk materials. Self-Assembled Nanostructures provides systematic coverage of basic nanomaterials science including materials assembly and synthesis, characterization, and application. Suitable for both beginners and experts, it balances the chemistry aspects of nanomaterials with physical principles. It also highlights nanomaterial-based architectures including assembled or self-assembled systems. Filled with in-depth discussion of important applications of nano-architectures as well as potential applications ranging from physical to chemical and biological systems, Self-Assembled Nanostructures is the essential reference or text for scientists involved with nanostructures.