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Author: Ryan Michael Schmidt Publisher: 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.
Author: Ryan Michael Schmidt Publisher: 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.
Author: Sebastian Ekeroth Publisher: 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.
Author: Andreas Schmidt-Ott Publisher: CRC Press ISBN: 1000730441 Category : Science Languages : en Pages : 292
Book Description
Spark ablation has been used worldwide for decades. However, in many fields, the special properties of nanoparticles, which come into play especially for sizes
Author: Thomas Laurell Publisher: Royal Society of Chemistry ISBN: 1849737061 Category : Technology & Engineering Languages : en Pages : 593
Book Description
The manipulation of cells and microparticles within microfluidic systems using external forces is valuable for many microscale analytical and bioanalytical applications. Acoustofluidics is the ultrasound-based external forcing of microparticles with microfluidic systems. It has gained much interest because it allows for the simple label-free separation of microparticles based on their mechanical properties without affecting the microparticles themselves. Microscale Acoustofluidics provides an introduction to the field providing the background to the fundamental physics including chapters on governing equations in microfluidics and perturbation theory and ultrasound resonances, acoustic radiation force on small particles, continuum mechanics for ultrasonic particle manipulation, and piezoelectricity and application to the excitation of acoustic fields for ultrasonic particle manipulation. The book also provides information on the design and characterization of ultrasonic particle manipulation devices as well as applications in acoustic trapping and immunoassays. Written by leading experts in the field, the book will appeal to postgraduate students and researchers interested in microfluidics and lab-on-a-chip applications.
Author: Christian Binek Publisher: Springer Science & Business Media ISBN: 9783540404286 Category : Science Languages : en Pages : 138
Book Description
Selected modern aspects of artificially layered structures and bulk materials involving antiferromagnetic long-range order are the main themes of this book. Special emphasis is laid on the prototypical behavior of Ising-type model systems. They play a crucial role in the field of statistical physics and, in addition, contribute to the basic understanding of the exchange bias phenomenon in MBE-grown magnetic heterosystems. Throughout the book, particular attention is given to the interplay between experimental results and their theoretical description, ranging from the famous Lee-Yang theory of phase transitions to novel mechanisms of exchange bias.
Author: Katsuhiko Ariga Publisher: Elsevier ISBN: 0323994733 Category : Technology & Engineering Languages : en Pages : 648
Book Description
Materials Nanoarchitectonics: From Integrated Molecular Systems to Advanced Devices provides the latest information on the design and molecular manipulation of self-organized hierarchically structured systems using tailor-made nanoscale materials as structural and functional units. The book is organized into three main sections that focus on molecular design of building blocks and hybrid materials, formation of nanostructures, and applications and devices. Bringing together emerging materials, synthetic aspects, nanostructure strategies, and applications, the book aims to support further progress, by offering different perspectives and a strong interdisciplinary approach to this rapidly growing area of innovation. This is an extremely valuable resource for researchers, advanced students, and scientists in industry, with an interest in nanoarchitectonics, nanostructures, and nanomaterials, or across the areas of nanotechnology, chemistry, surface science, polymer science, electrical engineering, physics, chemical engineering, and materials science. Offers a nanoarchitectonic perspective on emerging fields, such as metal-organic frameworks, porous polymer materials, or biomimetic nanostructures Discusses different approaches to utilizing "soft chemistry" as a source for hierarchically organized materials Offers an interdisciplinary approach to the design and construction of integrated chemical nano systems Discusses novel approaches towards the creation of complex multiscale architectures
Author: Vinay Raman Publisher: ISBN: Category : Languages : en Pages : 147
Book Description
This computational and theoretical study investigates the self-assembly of superparamagnetic nanoparticles and block copolymers under external magnetic fields. A variety of morphological transitions are observed based on the field orientation, nanoparticle loading, and selectivity of the nanoparticles for the blocks. For symmetric block copolymers, chaining of superparamagnetic nanoparticles under in-plane magnetic fields is shown to achieve long range orientational order of the block copolymer nanodomains and is found to be dependent on nanoparticle size, volume fraction and magnetization strength. A critical selectivity of the particles for one nanodomain is observed, above which strong alignment results and below which comparatively disordered structures are formed. Higher magnetization strengths are found to reduce equilibrium defect densities in the nematic-isotropic ordering of lamellar thin films, as corroborated by scaling arguments. For asymmetric coil fractions forming hexagonal block copolymer nanostructure, the inplane field induced chaining of the nanoparticles selective for the minority block, leads to the formation of stripe phases oriented parallel to the magnetic field. Furthermore, in-plane field induced chaining of nanoparticles selective for the majority block leads to alignment of hexagonal morphology with 100 direction oriented parallel to the external magnetic field. Out of plane magnetic fields induce repulsive dipolar interactions between the nanoparticles that annihilate the defects in the hexagonal morphology of the block copolymer when the nanoparticle is selective for the minority block. Honeycomb lattices are obtained using nanoparticles selective for majority block under out of plane magnetic fields for certain specific nanoparticle loadings. Commensurability of nanoparticle size and loadings with the block copolymer structure is critical in optimizing the ordering of the final composite. Kinetics of alignment in block copolymer nanocomposites is studied using External Potential Dynamics (EPD) method, wherein an equivalent evolution equation for potential fields is solved instead of conservation equation for the monomer segments. The dynamics study reveals an interesting interplay of nanoparticle mobility, dipolar interaction strength and nanoparticle-polymer interaction strength on the rate of alignment of domains.
Author: Ryan Michael Schmidt
Author: Ryan Michael Schmidt
Author: Peter John Krommenhoek
Author: 
Author: Sebastian Ekeroth
Author: Andreas Schmidt-Ott
Author: Thomas Laurell
Author: Xiaowei Teng
Author: Christian Binek
Author: Katsuhiko Ariga
Author: Vinay Raman